Otherworldly Patrons for Warlock missing

Hello everyone! I'm having an issue when creating my character: I'm creating a Warlock using Charactermancer, and when choosing my Otherworldly Patron, it only shows "The Fiend" option, my character was thought to have The Great Old One as a Patron. I looked for this in the forum and I saw a guy having this same problem 2 years ago ( right here ), but it has not advanced with a solution. Checking the link provided by Trivia ( Warlock Class ), I couldn't find there either the Patron I'm looking for, it just shows "The Fiend" Patron. Is there an issue? ot it just works like this and I should personalize my Otherworly Patron? Thanks in advance! Luke.

Do you own the Players handbook or are you in a campaign with a shared Players handbook? the other Patrons arent Part of the srd.

Oh, I just read about the SRD. I thought I could create my character with the players handbook characteristics. Didn't know about that limitation in the platform. (I'm new in this world, hehe)  I guess I will just personalize my Patron. Thanks Sven!