Sadi: You can not instigate phone verification on your own.
If Upwork feels like they need to verify your phone number or identity, they will contact you.
The ability to instigate this yourself is something that existed in the past, but is no longer a feature.
re: "Every freelancer has verifed mobile number. Have any problem if I do not verify mobile? Some days leter Can Upwork feel to verify mobile?"
I have never owned a mobile phone.
I have never had any problem working on Upwork and earning large sums of money here.
As Preston explained phone verification isn't currently available on Upwork. You shouldn't have any issues without verifying your phone number and they team will let you know if it's ever necessary.