You need to have a letter of invitation.
As I always suggest to all people going to any country, the traveller should have their bank statements (3 months is ideal), proof of address, and have a letter that fully states that they are invited, by who, where that person lives and where the visitor is going to stay.

(Obviously you don't need ALL that information, but it's always good to have it)

Then the person can apply for a tourist visa.
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