Hi @Laraib and welcome to the forum!
You’re not going to be able to accomplish that requirement using the Asana interface. The only way to accomplish it is by using the Asana API to provide Asana’s data and then write your own UI to handle that data. (Honestly if it was me and I had that requirement, I probably would not use Asana but would just create my own data store to go along with my desired UI. Why would you use Asana in that use case?)
You can do this using the Asana API, sort of. You can’t add a user to Asana per se, but you can generate an invitation for them to join using the addUser
endpoint; for details see:
and also this forum topic: