How do I add files with different names into separate jobs?

i have many files in 1 folder. how can i quickly create multiple jobs so 1.mp4 and are in 1 job, and 2.mp4 and are in another job? thank you

Using a shell such as bash I’d probably do something like this:

for idx in {1..50} ; do
  mkvmerge -o ${idx}.mkv ${idx}.mp4 ${idx}.srt

You can easily do similar things with scripting languages such as Python or even in PowerShell.

And if your file names aren’t just numbers, but each MP4 & each SRT share the same base name, you can do something simliar:

for mp4_name in *.mp4; do
  mkvmerge -o ${mp4_name%mp4}.mkv ${mp4_name} ${mp4_name%mp4}.srt

Or look into one of the third-party batch muxing GUIs.