how do I add a phone number from a text message to my contacts

If you mean the number that texted you, tap on the number, then tap the “info” icon just below the number, then Create new contact or Add to Existing Contact.

If the number is in the body of the message tap on it and choose Copy, then paste it into a contact.

Hello ~ Any help by clicking on the link below? It’s a prior post and the Community Specialist answer may be of help …give it a try and post back and let me know how it works for you?

Problem adding contact from text - Apple Community

~Katana-San~