After the word "to" do you always use the present tense? e.g I am looking forward to see you.
Always....No. Sometimes we use the gerund, that is, Verb+ING, after 'TO'.

Many times the verb is in gerund (-ing form) after a preposition.
I'm looking forward to SEEING you.
Thank you for COMING.

NOTE: 'TO' is not always a preposition. Sometimes it is the first part of an infinitive.
Infintive = to go, to eat, to smile, to think.....
When we have to verbs together, normally the second verb is in the infinitive.
I want TO sleep. I need TO see a psychologist.

EXCEPTION: Modal verbs (must, might, should...)
- You must study more if you want to pass the test.
- We should go and have a drink.
In these cases, we don't use the TO.
AnonymousWhere do we use a gerund after to?
When 'to' is a preposition and not the infinitive particle.
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where we use gerund after to
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GuestAfter the word "to" do you always use the present tense?
Notice that the verb form you refer to is not 'present tense': it is the bare infinitive or dictionary form of the verb.