"Giving access to" something means giving someone the permission to use it. For example, giving someone access to a room would mean giving them a key. Giving them access to a computer system would mean giving them a login ID and password.
Can you give me access to the admin page so I can delete some unused accounts?
We use the word "access" a lot when talking about computer systems, passwords, security, information, and so on. Here are some other examples of phrases using "access":