If yes under which tree will it be inputted
Hi @Emeonye, Martins thanks for your question. You can kindly read through the article below which may help with your question.
Of course it is. You can do any kind of research you want for anyone in the world. Family Tree is a single, worldwide, wiki-style tree that allows us all to work anywhere we have interest. There is only one tree into which everything is inputted.
Now to rephrase your question, "if yes under which tree will it be inputted," since there is just the one tree, to the more pertinent question, "if yes, under which account will it be inputted," it is important to keep in mind that any living people entered in your account will only be visible to you. A friend of neighbor will never be able to see them.
So you have two choices:
1) Only do family history research for the deceased family of friends and neighbors and enter the results into Family Tree. That is, only start family lines with the first deceased individual on each direct line back. Anyone in the world can see all deceased people. (Except for certain sensitive situations.)
2) Have each friend of neighbor you are going to do this for open his or her own FamilySearch account. Then go to the Help menu, choose Helper Resources, and in the Planner section, invite each of them to let you be a helper for their accounts:
Then when you are working on a living person in a family, go to the planner and function as a helper for the correct account. This allows you full access to that person's Family Tree information including living people. Only add living people to Family Tree as a Helper. Then your friend or neighbor can go in to his or her own account and see all your work for them including any living people.
(If your friend or neighbor has any family lines that trace back to sensitive groups then you should do all research for them as a Helper or they won't be any to see even deceased people. See: https://www.familysearch.org/help/helpcenter/article/deceased-people-in-my-family-tree-private-space ).
I could really use this Helper feature. As best I can tell, only an LDS member account can be a Helper. Is that correct?
Also, at the bottom of https://www.familysearch.org/help/helpcenter/article/where-do-i-find-my-helper-number is a link "How do I revoke access to partners and helpers?" I am not able to read that help article. I get an error message "This page contains information for members of The Church of Jesus Christ of Latter-day Saints. Church membership can be linked to your account at registration or by going to your Account Settings."
Thank you for posting in the Community. If you are working with a friend or a neighbor, it is best that they create their own free FamilySearch account. Then starting with themselves, add the living individuals (parents and maybe grandparents) on each line, until they get to the first deceased individual, (because FamilySearch protects the privacy of living people). After that they will be able to view all deceased ancestors already in Family Tree.