Main Similarity and Difference
'We' and 'they' are both plural personal pronouns, but 'we' is the first-person personal pronoun, and 'they' is the third-person personal pronoun. Here, we will discuss these two.
We: Subject Pronoun
'We' is used as the subject of a verb. When the subject of a sentence (the one that does the action of the verb) is 'one or more people including us', we use the pronoun 'we'.
People in General
'We' can also refer to people in general.
In the academic context, writers or speakers use 'we' instead of 'I' to involve the readers or listeners in the process of what is being said or written.
The Royal We
In the past, kings, queens, judges, etc. referred to themselves using 'we' instead of 'I'. This is called 'the royal we' or 'majestic plural'.
Sarcasm or Encouragement
Sometimes, people use 'we' instead of 'you' to either sound sarcastic or condescending; or sound persuasive or encouraging.
If we want to clearly refer to a group of people and we want to put emphasis on that, we can put 'we' before nouns.
'They' is a third-person pronoun. It is used as the subject of a verb. 'They' refers to a group of people, animals, or things.
The Singular They
'They' is used instead of 'he' or 'she' to refer to a person whose sex is not mentioned or is unknown. This is called the 'singular they'.
We can use 'they' to refer to people in general, especially when we want to say a general idea or a famous saying.