We fill in the forms for hotel booking and the deals appear.
" Deal will appear on the screen after you fill in the form."
If I write this like "Once you fill the form, the deals will populate on your screen as per your inputs" will it be correct?
It's not correct diction; "populate" in this sense is a /transitive verb/.
This means someone or something must be "doing" the populating; they were not there before, now they are - I have populated them.
Compare with "appear" - they were not there before, now they are - They appeared.
No one has "appeared them" - because that's an intransitive verb.
You should be able to replace "place" with "populate" ('I placed/populated the deals') and 'be found' with 'appear' ('The deals will be found on your screen...')