GOOGLE SHEET VBA

For a low-budget Startup, I prepare a google spreadsheet that I would like to use to help my small customers.
I know a bit about coding but not enough to do the job I want to do.
However, the task is easy but requires good precision.

HERE ARE SOME DETAILS OF WHAT I'M LOOKING FOR:
SOFTWARE TO ENTER CLIENT IN CLIENT LIST
WE BUILD A CLIENT LIST
SOFTWARE THAT ACCESSES CLIENT LIST WITH SEARCH BOX
SOFWARE THAT ALLOW TO EDIT CLIENT'S ACCOUNT
SECTION IN SOFTWARE WHERE PLANS ARE STORES
SOFTWARE MUST ALLOW PLACE SELECTION AND ACCESS
SOFTWARE MUST ALLOW AUTOMATIC CONTRACT FILL OUT
NEED NOTE SECTION WITH AUTOMATIC DATE AND TIME
CHANE TO NEXT BOX WHEN PRESS TAB OR ENTER
ALLOW SPECIAL SERVICES DATES TO BE SEEN ON THE MAIN PAGE
MULTIPLE USERS CAN MODIFY AT THE SAME TIME WITHOUT AFFECTING THE OTHER

CONDITIONS:
For the sole purpose of saving time, me and the chosen one for this project will work together from our screen in sharing mode, this will facilitate immediate answers to questions for more acuity.

I await your news.

Thank you

K
NB.- I am also open to winning proposals