You can add an Official Account to your Friends list by doing the following:

▼Select the Official Account from the list
1. Tap More > Add Friends > Official to open the Official Accounts list.
2. Tap the Official Account you wish to add to your Friends list, and tap Add.

▼Search by ID
1. Tap More > Add Friends > Search by ID and enter the ID of the account you want to search for.
2. Tap Add and the account will be added to your Friends list.