How can I send a file?
Use Threema to send files of any type (PDF, animated GIF, MP3, DOC, ZIP, etc.). Just like all other messages, files are end-to-end encrypted. The maximum file size is 50 MB. To avoid compression of an image or video, you can send it as file. Please note: If you send an image as file, its EXIF tags (possibly containing information such as the date and location the image was taken) are preserved.
Android: In a chat, tap on the paperclip icon, and select “File”.
iOS: In a chat, tap on the “+”, and select “Send file”. Due to restrictions of iOS regarding the file system, you can only access content of apps that support file sharing.
Windows Phone: Currently not available. Files cannot be received.