Complete is usually an adjective. For some of its meanings, you can use words like more and very in front of it.
used to mean ‘as great as possible’
You usually use complete to say that something is as great in degree, extent, or amount as possible.
You need a complete change of diet.
They were in complete agreement.
When complete has this meaning, you do not use words like more or very in front of it.
used to talk about contents
Complete is also used to say that something contains all the parts that it should contain.
I have a complete medical kit.
...a complete set of all her novels.
When two things do not contain all the parts that they should contain but one thing has more parts than the other, you can say that the first thing is more complete than the second one.
For a more complete picture of David's progress we must depend on his own assessment.
Similarly, if something does not contain all the parts that it should contain but contains more parts than anything else of its kind, you can say that it is the most complete thing of its kind.
...the most complete skeleton so far unearthed from that period.
used to mean ‘thorough’
Complete is sometimes used to mean thorough. When complete has this meaning, you can use words like very and more in front of it.
She followed her mother's very complete instructions on how to organize a funeral.
You ought to have a more complete check-up if you are really thinking of going abroad.
used to mean ‘finished’
Complete is also used to say that something such as a task or new building has been finished.
It'll be two years before the process is complete.
...blocks of luxury flats, complete but half-empty.
When complete has this meaning, you do not use words like ‘more’ or ‘very’ in front of it.