Collins Dictionary has a nice and comprehensive article on phrasal verbs.
A phrasal verb is a type of verb that is created when a main verb is combined with either:
get at (someone)
pick on (weaker children)
or an adverb + preposition,
put up with (insults)
get out of (doing something)
Type A. Verb
Some Type A phrasal verbs have no object, i.e. they are intransitive. The sentence makes sense without any further addition to the verb.
Mary went away.
Helen sat down.
Others do require an object, i.e. they are transitive.
We could make out a figure in the distance.
He tried to blow up the Houses of Parliament.
Could you put your clothes away, please?
If the object is a noun, many Type A phrasal verbs will allow the adverb to come either:
before the object,
I picked up Jim on my way home.
He blew out the candle.
or after the object.
I picked Jim up on my way home.
He blew the candle out.
Please note the part of the answer below, because it is especially germane to your question:
Sometimes you can guess the meaning of these verbs from the meanings of the parts.
to sit down = sit + down
to go away = go + away
Sometimes you have to learn the new meanings, or use a dictionary.
to make up (an answer) = invent
to turn down (an invitation) = decline
Type B. Verb plus preposition
Type B phrasal verbs always have an object. This is because prepositions always have an object.
He asked for his bill.
He asked for it.
Sometimes there are two objects – the object of the verb and the object of the preposition.
He asked the waiter for the bill.
Type C. Verb plus adverb and preposition
Type C phrasal verbs are a combination of the two previous kinds of verb. All the parts of a Type C phrasal verb come before the object.
We are looking forward to our holiday/it.
Don’t put up with bad behaviour/it.
It is sometimes hard to tell adverbs and prepositions apart, because often the same word can be both a preposition and an adverb, depending on how it is used. For further information about prepositions see Prepositions.
The following are examples of the three types of phrasal verb that are explained on Phrasal verbs.
Phrasal verbs made from a verb plus an adverb may be intransitive (do not take an object) or transitive (take an object).
some phrasal verbs that
do not take an object some phrasal verbs that
do take an object
to break down to blow something up
to carry on to break something off
to fall down to bring a child up
to get about to bring a subject up
to get up to catch somebody up
to give up to clear something up
to go away to close something down
to go off to give something up
to go on to leave something out
to grow up to make something up
to hold on to pick someone up
Phrasal verbs made from a verb plus a preposition are all transitive.
to add to something to hope for something
to agree with someone to insist on something
to apply for a job to laugh at something
to approve of something to listen to something
to arrive at a place to look after someone
to ask for something to look for something
to believe in something to look into something
to belong to someone to pay for something
to call on someone to refer to something
to care for someone to rely on someone
to come across something to run into someone
to deal with something to run over something
Some Type B verbs are doubly transitive, since both the verb and the preposition can have an object.
to add insult to injury
to ask a grown-up for help
to check your answers with the teacher
to pay the assistant for your shopping
to refer a customer to the manager
Phrasal verbs with an adverb plus a preposition all take a prepositional object.
to be fed up with something to keep away from something
to carry on with something to look back on something
to catch up with something to look forward to something
to check up on something to look out for something
to come up with something to look up to someone
to cut down on something to make up for something
to do away with something to put in for something
to face up to something to run away with something
to fall back on something to run out of something
to get on with someone to run up against something
to get out of something to stand up for something
to go back on something to walk out on someone
to go in for something to watch out for something
to break in on someone to lead up to something