Both forms are correct. Both forms – too and to – are correct and their spelling is very alike, but this is where the similarities end. Too is a simple adverb with a few possible meanings, and to is a completely different story. As a preposition, to doesn’t carry any specific meaning but takes an important part in creating other forms. It can be used before a noun, noun phrase, or pronoun or after nouns, after certain verbs (be used, get used, listen, look forward, object, reply, respond) or adjectives (mostly indicating feeling or behavior). To also creates a to-infinitive structure with verbs. There are multiple connections, phrases, and indications that to forms.

Correct spelling, explanation: a simple adverb with a few possible meanings, please read the definition and examples.

Correct spelling, explanation: a preposition, please read the definition and examples.

Definition of too:
adverb: more than wanted, more than necessary;
There are too many people here and it is too hard for me to handle.
– also;
Can I come too? It should be fun.
– completely, very;
I would prefer a simple ceremony, nothing too fancy.

How to use to?:
– the to-infinitive: before a verb to create the to-infinitive form;
She wanted to come but was held up at work.
– to indicate direction or destination;
Do you want to go to the museum with us?
– to indicate the receiver of action with verbs like give, hand, send, write;
I gave my word to John and I won’t let him down.
– an indication of time; to tell the hour, how much time until an event or with the expression from … to…;
We have only two days to Christmas and then we are going to visit my parents, we will be gone from Wednesday to Friday.
– to point out an approximate number;
I will probably cost like seventy to eighty dollars, but I will give you a hundred just to be sure.