Use an online converter
Upload the MP4 file
Choose GIF as the output format
Adjust size, frame rate, and start/end time if needed
Convert the file
Download the GIF
Use VLC or another video editor
Open the MP4 file
Trim the clip to the desired section
Export or save as GIF if supported
If GIF export is not available, use a dedicated converter
Use Photoshop
Open the MP4 file as frames
Select the portion you want
Export as GIF
Use FFmpeg
Install FFmpeg
Run a command to convert MP4 to GIF
Example: ffmpeg -i input.mp4 output.gif
Use mobile apps
Import the MP4 file
Select GIF export
Save the converted GIF