1// Create file 
2React-native cli project or with --template typecript
3
4react-native.config.js
5
6======ADD==========
7module.exports = {
8  assets: ['./src/assets/fonts'],
9}
10
11=======run===========
12react-native link
13after that check your info.plist
14
15must font must be there to use in application 
16
17<key>UIAppFonts</key>
18<array>
19  <string>Comfortaa-Bold.ttf</string>
20  <string>Comfortaa-Light.ttf</string>
21  <string>Comfortaa-Medium.ttf</string>
22  <string>Comfortaa-Regular.ttf</string>
23  <string>Comfortaa-SemiBold.ttf</string>
24</array> 
25
26
27and for andrid like all the files should be like this
28
29Your_app_name /android/app/src/main/assets/fonts
30aLL of you fonts file comes here
31
321// create a folder in your root directory /assets/fonts/ 
2// paste the custom fonts you want used in that folder
3// create a file in the root called react-native.config.js
4// Then add the following:
5
6module.exports = {
7  project: {
8    ios: {},
9    android: {},
10  },
11  assets: ['./assets/fonts'],
12};
13
14// then run 
15
16react-native link