I cant choose twilio phone number

it shows that “Trial accounts must verify a phone number before purchasing a Twilio number.”

Enter your personal mobile no. to get verified and then it activates the Twilio account and no.

You have to add your phone number and verify it first before choosing the Twilio number.
Go to Dashboard there you will find verified numbers in yellow highlight, press it first give ur number and verify. Now choose a Twilio number.