Archives collect and preserve original documents of organizations such as churches or governments. Libraries generally collect published sources such as books, maps, and microfilm.
If you plan to visit a repository, contact them and ask for information about their collection, hours, services, and fees. Ask if they require you to have a reader’s ticket (a paper indicating you are a responsible researcher) to view the records, and ask how to obtain one.
Although the records you need may be in an archive or library, the FamilySearch Library may have microfilmed and/or digitized copies of them.