All phrasal verbs
in
/ɪn/23 verbsVowel-initial — links backwardsSomething moves into a space, a group, or a person's hands.
IN is entry, but the entry is often social or administrative rather than physical: hand in a report, check in at a hotel, fill in a form, give in to pressure.
The pairing to watch is fill in vs fill out — both mean completing a form, and in American English fill out is the default for the whole document while fill in suits a single blank.
What it does to the sound
IN reduces heavily. The vowel is a short /ɪ/ and in fast speech it can collapse toward a schwa, which is why give in sounds like “gi-vin”. Do not give it a long EE — that is the vowel of green, not in.
What IN means
Submitting — deliver to an authority
Something is given to the person who requires it.
Every verb that takes IN
The complete list — 23 of them. The section above groups the common ones by what IN is doing.