You can currently change the font on the Label and TextInput components by setting their FontFamily property (in the Advanced tab). The available font choices differ depending on the device type (i.e. Android or iOS) and are listed below. At some point we will likely allow you to choose a font for each device type and perhaps make the choice be a dropdown (at least for Android, where there are many fewer choices). We will also likely enable setting the font for Button components as well.
List of available Android fonts:
normal
notoserif
sans-serif
sans-serif-light
sans-serif-thin
sans-serif-condensed
sans-serif-medium
serif
Roboto
monospace
List of available iOS fonts:
San Francisco
Academy Engraved LET
AcademyEngravedLetPlain
Al Nile
AlNile-Bold
American Typewriter
AmericanTypewriter-Bold
AmericanTypewriter-Condensed
AmericanTypewriter-CondensedBold
AmericanTypewriter-CondensedLight
AmericanTypewriter-Light
Apple Color Emoji
Apple SD Gothic Neo
AppleColorEmoji
AppleSDGothicNeo-Bold
AppleSDGothicNeo-Light
AppleSDGothicNeo-Medium
AppleSDGothicNeo-Regular
AppleSDGothicNeo-SemiBold
AppleSDGothicNeo-Thin
AppleSDGothicNeo-UltraLight
Arial
Arial Hebrew
Arial Rounded MT Bold
Arial-BoldItalicMT
Arial-BoldMT
Arial-ItalicMT
ArialHebrew
ArialHebrew-Bold
ArialHebrew-Light
ArialMT
ArialRoundedMTBold
Avenir
Avenir Next
Avenir Next Condensed
Avenir-Black
Avenir-BlackOblique
Avenir-Book
Avenir-BookOblique
Avenir-Heavy
Avenir-HeavyOblique
Avenir-Light
Avenir-LightOblique
Avenir-Medium
Avenir-MediumOblique
Avenir-Oblique
Avenir-Roman
AvenirNext-Bold
AvenirNext-BoldItalic
AvenirNext-DemiBold
AvenirNext-DemiBoldItalic
AvenirNext-Heavy
AvenirNext-HeavyItalic
AvenirNext-Italic
AvenirNext-Medium
AvenirNext-MediumItalic
AvenirNext-Regular
AvenirNext-UltraLight
AvenirNext-UltraLightItalic
AvenirNextCondensed-Bold
AvenirNextCondensed-BoldItalic
AvenirNextCondensed-DemiBold
AvenirNextCondensed-DemiBoldItalic
AvenirNextCondensed-Heavy
AvenirNextCondensed-HeavyItalic
AvenirNextCondensed-Italic
AvenirNextCondensed-Medium
AvenirNextCondensed-MediumItalic
AvenirNextCondensed-Regular
AvenirNextCondensed-UltraLight
AvenirNextCondensed-UltraLightItalic
Bangla Sangam MN
Baskerville
Baskerville-Bold
Baskerville-BoldItalic
Baskerville-Italic
Baskerville-SemiBold
Baskerville-SemiBoldItalic
Bodoni 72
Bodoni 72 Oldstyle
Bodoni 72 Smallcaps
Bodoni Ornaments
BodoniOrnamentsITCTT
BodoniSvtyTwoITCTT-Bold
BodoniSvtyTwoITCTT-Book
BodoniSvtyTwoITCTT-BookIta
BodoniSvtyTwoOSITCTT-Bold
BodoniSvtyTwoOSITCTT-Book
BodoniSvtyTwoSCITCTT-Book
Bradley Hand
BradleyHandITCTT-Bold
Chalkboard SE
ChalkboardSE-Bold
ChalkboardSE-Light
ChalkboardSE-Regular
Chalkduster
Chalkduster
Cochin
Cochin-Bold
Cochin-BoldItalic
Cochin-Italic
Copperplate
Copperplate-Bold
Copperplate-Light
Courier
Courier New
Courier-Bold
Courier-BoldOblique
Courier-Oblique
CourierNewPS-BoldItalicMT
CourierNewPS-BoldMT
CourierNewPS-ItalicMT
CourierNewPSMT
Damascus
DamascusBold
DamascusLight
DamascusMedium
DamascusSemiBold
Devanagari Sangam MN
DevanagariSangamMN
DevanagariSangamMN-Bold
Didot
Didot-Bold
Didot-Italic
DiwanMishafi
Euphemia UCAS
EuphemiaUCAS-Bold
EuphemiaUCAS-Italic
Farah
Futura
Futura-CondensedExtraBold
Futura-CondensedMedium
Futura-Medium
Futura-MediumItalic
Geeza Pro
GeezaPro-Bold
Georgia
Georgia-Bold
Georgia-BoldItalic
Georgia-Italic
Gill Sans
GillSans-Bold
GillSans-BoldItalic
GillSans-Italic
GillSans-Light
GillSans-LightItalic
GillSans-SemiBold
GillSans-SemiBoldItalic
GillSans-UltraBold
Gujarati Sangam MN
GujaratiSangamMN
GujaratiSangamMN-Bold
Gurmukhi MN
GurmukhiMN-Bold
Heiti SC
Heiti TC
Helvetica
Helvetica Neue
Helvetica-Bold
Helvetica-BoldOblique
Helvetica-Light
Helvetica-LightOblique
Helvetica-Oblique
HelveticaNeue-Bold
HelveticaNeue-BoldItalic
HelveticaNeue-CondensedBlack
HelveticaNeue-CondensedBold
HelveticaNeue-Italic
HelveticaNeue-Light
HelveticaNeue-LightItalic
HelveticaNeue-Medium
HelveticaNeue-MediumItalic
HelveticaNeue-Thin
HelveticaNeue-ThinItalic
HelveticaNeue-UltraLight
HelveticaNeue-UltraLightItalic
Hiragino Mincho ProN
Hiragino Sans
HiraginoSans-W3
HiraginoSans-W6
HiraMinProN-W3
HiraMinProN-W6
Hoefler Text
HoeflerText-Black
HoeflerText-BlackItalic
HoeflerText-Italic
HoeflerText-Regular
Iowan Old Style
IowanOldStyle-Bold
IowanOldStyle-BoldItalic
IowanOldStyle-Italic
IowanOldStyle-Roman
Kailasa
Kailasa-Bold
Kannada Sangam MN
KannadaSangamMN
KannadaSangamMN-Bold
Khmer Sangam MN
Kohinoor Bangla
Kohinoor Devanagari
Kohinoor Telugu
KohinoorBangla-Light
KohinoorBangla-Regular
KohinoorBangla-Semibold
KohinoorDevanagari-Light
KohinoorDevanagari-Regular
KohinoorDevanagari-Semibold
KohinoorTelugu-Light
KohinoorTelugu-Medium
KohinoorTelugu-Regular
Lao Sangam MN
Malayalam Sangam MN
MalayalamSangamMN
MalayalamSangamMN-Bold
Marker Felt
MarkerFelt-Thin
MarkerFelt-Wide
Menlo
Menlo-Bold
Menlo-BoldItalic
Menlo-Italic
Menlo-Regular
Mishafi
Noteworthy
Noteworthy-Bold
Noteworthy-Light
Optima
Optima-Bold
Optima-BoldItalic
Optima-ExtraBlack
Optima-Italic
Optima-Regular
Oriya Sangam MN
OriyaSangamMN
OriyaSangamMN-Bold
Palatino
Palatino-Bold
Palatino-BoldItalic
Palatino-Italic
Palatino-Roman
Papyrus
Papyrus-Condensed
Party LET
PartyLetPlain
PingFang HK
PingFang SC
PingFang TC
PingFangHK-Light
PingFangHK-Medium
PingFangHK-Regular
PingFangHK-Semibold
PingFangHK-Thin
PingFangHK-Ultralight
PingFangSC-Light
PingFangSC-Medium
PingFangSC-Regular
PingFangSC-Semibold
PingFangSC-Thin
PingFangSC-Ultralight
PingFangTC-Light
PingFangTC-Medium
PingFangTC-Regular
PingFangTC-Semibold
PingFangTC-Thin
PingFangTC-Ultralight
Savoye LET
SavoyeLetPlain
Sinhala Sangam MN
SinhalaSangamMN
SinhalaSangamMN-Bold
Snell Roundhand
SnellRoundhand-Black
SnellRoundhand-Bold
Symbol
Tamil Sangam MN
TamilSangamMN-Bold
Telugu Sangam MN
Thonburi
Thonburi-Bold
Thonburi-Light
Times New Roman
TimesNewRomanPS-BoldItalicMT
TimesNewRomanPS-BoldMT
TimesNewRomanPS-ItalicMT
TimesNewRomanPSMT
Trebuchet MS
Trebuchet-BoldItalic
TrebuchetMS-Bold
TrebuchetMS-Italic
Verdana
Verdana-Bold
Verdana-BoldItalic
Verdana-Italic
Zapf Dingbats
ZapfDingbatsITC
Zapfino
