Are you trying to figure out how to change your relationship status on Facebook from your phone? This guide is for you.
Steps

Step 1. Open Facebook mobile on your phone or other mobile device
Click on the icon in the left corner with three lines on it.

Step 2. Press your name
This will take you to your profile.

Step 3. Right below your profile picture, there should be a rectangle called "Information about you" underlined
Press it.

Step 4. Scroll down the page until you see a section called Relationship
If no one is selected, this box should say "Add a relationship." If there is, then there should be a button next to it that says "edit." Press any of the two that appears.

Step 5. Press the status of your current sentimental situation (it should be in blue), and go down the menu that will appear
Select the appropriate romantic situation.

Step 6. Unless you have chosen "single", "divorced", or "widowed", there will be more options to specify your partner from your friends list and an anniversary date

Step 7. To choose a partner, start typing their name and click on the correct one
Note: by doing this, a "Request for change in romantic situation" will be sent to your partner. Until approved by your partner, your status will appear as "(pending)" when you view your own profile and other people will not see their name. However they will see if you are in a relationship / marriage / etc.

Step 8. Click save to post your new relationship situation
Advice
- If you're going to post your new relationship with your partner, be sure to check it out first.
- It is generally very frowned upon to break up with someone by changing your relationship on Facebook.