Shlichus (and mivtzoim) are just the Chabad terms for their version of outreach, or kiruv as it’s called among most Jews. (The Rebbe objected to the term kiruv for the reason chabadgal mentions.) They don’t put any pressure on people or try to convince them Yiddishkeit is true, but instead just teach and serve as inspiring examples and hope that people are motivated to make their own decisions to take on more mitzvos. Breslov tends to use the term hafatza instead of kiruv.
Some non-Chabad, especially Litvish, kiruv rabbis are known to be a little more high-pressure, trying to convince people logically that Torah is true and getting them into BT yeshivas that help them quickly become completely frum. Still, not even they “force” people to be frum, which is impossible anyway.