Exporting Adobe premiere File as MP4

(from Adobe Premiere support (Links to an external site.))

1. To export a sequence as an H.264 file (the most popular option), make sure the Timeline panel is active and choose File > Export > Media or press Control+M (Windows) or Command+M (macOS).
2. In the Export Settings dialog box, choose Format: H.264 and Preset:Match Source – High Bitrate. 
   (Note: In order to save as an mp4 you will need to make sure you select the H.264 format and not MPEG4)
   
   
3. To choose a filename and location, click the blue filename to open the Save As dialog box. Use this to choose an export location and a name for your new file, and then click Save.
   
   
4. When you’re happy with your settings, click Export. The new video file will be created, ready to share with the world.