"Too" means also or more.
- Correct usage
- He would like to go too.
- That is too much sugar.
- The two children are too near to the fire.
- Incorrect usage
- The too children are to near too the fire.
"Two" is a number. (It comes after one and before three.) It's also written as "2".
"To" is a preposition indicating something is going or getting nearer to something else.