Does this work like google drive where multiple people can simultaneously edit a document at the same time? thx.
Yes, if you mean OnlyOffice or Collabora.
What are those add-ons? I am not familiar with them. I just need two (or more) people to be able to edit simultaneously. Thanks!
Yes, for that try OnlyOffice with the community document server addon that was newly introduced in Nextcloud18. It works for 3-5 people usually fine, but it is quite new and there are some bugs and missing functionality with it.