Verb + てもいい is a construction in Japanese used to express that something is ‘okay’, or ‘alright’. It can also be used as a question to ask if you ‘can’, or ‘may’ do something.
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その靴（くつ）を買（か）ってもいいよ。
It’s alright if you buy those shoes.
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この肉（にく）は食（た）べてもいいです。
It is okay to eat this meat.
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明日（あした）は家（いえ）に行（い）ってもいいですか？
Is it okay if I go to your house tomorrow?
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ペンを借（か）りてもいいですか？
May I borrow your pen?
This phrase is also regularly used without the
も, but is considered a bit more direct/casual. It is best to remove the
も only when talking to people that you know well.
This expression is simply a construction that literally means
て (verb)
も (also)
いい (is good).
As this grammar point uses the て form of verbs, it is important to remember that some verbs will use で instead of て.