This one’s hard to explain, so pay attention.
Access as Verb
When used as a verb, “access” it is not followed by “to.” Just write:
“Thanks to the Internet, I can access information at any time.”
“Students can access a lot of books at the campus library.”
“Everyone wants to access the Internet nowadays.”
This is the most common use of the word, I think.
Access as a Noun
When used as a noun, “access” should be followed by “to.” As in:
“Thanks to the Internet, students have access to a lot of information.”
“Students who visit the library have access to a lot of books.”
“Student wants access to more books.”
Don’t Write “access (v) to”
The most common error I see is when students use “access” as a verb and write “to” after it. This will always be wrong. Don’t write:
On the Internet, students can access to a lot of information at any time.”