Best file picker for react native

On a personal opinion, I use react-native-document-picker.

The installation and the usage is well mentioned in their docs

Right now it supports most general use cases required for file upload

• All type of Files 'public.allFiles' or DocumentPickerUtil.allFiles()
• Only PDF 'public.pdf' or DocumentPickerUtil.pdf()
• Audio 'public.audio' or DocumentPickerUtil.audio()
• Plain Text 'public.plainText' or DocumentPickerUtil.plainText()

The rest of the restrictions can be modified based upon your file type option as it provides with the following file res options

 res.uri,
 res.type, // mime type
 res.fileName,
 res.fileSize