Good Relationship
Friends
After that if you keep moving to the good side you will become Friends. This status doesn’t need to send any request.
Good Friends
if you keep moving to the good side and give your friend good relation, you will become Good Friends. You need to send a request to become a Good Friends to your friend.
Close Friends
keep the good interaction and you will become Close Friends. You need to send a request for this status.
Best Friends
after being a Close Friends keep doing a good interaction, and you will become a Best Friend. You need to send a request for this status.
BFF
keep doing the good interaction till the relation bar get into the next status at the right side. and you will become BFF! You need to send a request for this status.
BFF+
This one is the highest status of friends relationship, and to gain this status you don’t need to send any request, because when the relation bar touch the right side, it will be automatically updated.
P.S: The higher you get status in a relationship you will getting harder to keep it into that state. For e.g to keep your friend in Close Friend will be much easier then keeping your friend in BFF+ status.
See also:
The Sims Social: Romantic Relationship
The Sims Social: Mean Relationship
Thank you for visitting !
~rhazchan 
