Add Other Relationships • FamilySearch

In Family Tree, you can add Other Relationships to connect individuals who were not family or whose family relationship cannot be identified.

Steps (website)

In Family Tree, go to the person page of the individual with the relationship you want to add.
Click Details.
Scroll down to the Other Relationships section (near the bottom of the page).
Click + Add Other Relationship.
Click + Add Person.
In the drop-down menu, select the relationship type.
If the individuals are shown with the wrong roles, click the Switch icon .
Click Save.
Enter a reason statement to show why you know the changes are correct. This will help other users understand the change and discourage people from making inaccurate changes in the future.
Click Save.
To add events, sources, and notes about this relationship, click the Edit icon . (Tip: We recommend adding the sources and notes to the person, in addition to the relationship. That makes them easier for other users to see.)

In the Family Tree mobile app, display the person page that you want to enhance.
Tap Details.
Tap the plus sign in the circle at the bottom right.
Scroll down to the bottom of the list, and tap Other Relationship.
Tap to select the relationship type.
Tap + Add Person.
Enter information about the person, and tap Continue. (If you know the ID, tap Add by ID or Find by ID.)
Indicate whether the individual is living or deceased, and then tap Continue.
Review the search results. If you find the right person, tap Select. If you do not see the person in the search results, tap No Match. 
If the individuals are shown with the wrong roles, click the Switch icon (insert icon).
Tap Save.
As needed, add events and notes about this relationship.