Hello @Kanki
Welcome to UiPath Community!
For the first problem, you can try different method options given below
Also, if you know the tab index of the textbox you can use send hotkey activity to traverse your textbox and then use type into.
For the popups you can use activities like OnElementAppear, If ElemenExists
You can first try to search this on Forum also there are many similar topics with solution
like this one
Thanks,
Prankur