How does the grammar of phrasal verbs work?

First of all phrasal verbs are verbs, so, they can be conjugated in any tense. They have a past, a present, a future, a continuous, and a perfect form. So, don’t forget to use them correctly.

Next there are 2 different kind of phrasal verbs, 1 where you can separate the particle (preposition,..) from the verb, and others where you can’t.

Separable

• I need to fill in the forms 
• I need to fill the forms in

Fill in: write some information on a paper or document.

As you can see here you can use both you can put ‘the forms’ between the verb and the particle or you can put it after. Both are good.

Exception

When you are using pronouns (it, they,….) you always need to put the pronoun between the verb and the particle.

• I need to fill in the forms
• I need to fill it in.

Non-sperabale 

I really don’t know, but I will look into it

Look into: investigate

You cannot say: I will look it into.

Phrasal verbs which have 2 particles are always inseparable.

• I can’t put up with this noise anymore.
• I can’t put up with it anymore.

You can’t say: I can’t put it up with anymore