H4 EAD along with H1B/H4 extension

[ab's]

I read in many other threads that you can write H1B extension receipt number in spouse H4 EAD application form as I-797 #.
I am not sure if i will have H1B receipt at time filling H4 EAD form as i am applying all togther.

Please advice if anyone has experince applying EAD along with H1 extension.

Which I-797 # you wrote in EAD applocation and what was the validity you received for EAD?