Social Interactions. The GM determines to what extent social interactions between characters and non-playing characters and creatures are controlled by ability checks, player ingenuity, the GM's desire to control the outcome, or some combination of these. See PHB p. 186 and DMG p. 244 for guidance. Either way, try roleplaying when interacting.
If an ability check is required, the GM decides which check is applicable to the situation:
A Charisma check might arise when you try to influence or entertain others, when you try to make an impression or tell a convincing lie, or when you are navigating a tricky social situation. The Deception, Intimidation, Performance, and Persuasion skills reflect aptitude in certain kinds of Charisma checks.
Your Wisdom (Insight) check decides whether you can determine the true intentions of a creature, such as when searching out a lie or predicting someone’s next move.
The GM decides the task's Difficulty Class.
The DC depends on what you seek, the risk it poses to the creature you communicate with, and the creature's attitude.
A creature's attitude reflects its alignment, among other things, and can be influenced positively or negatively by the character's behavior as well as one or more elements of the character's identity.
The GM also decides if the circumstances warrant the application of advantage or disadvantage. See also Aiding the Check (DMG p. 245), Parleying with Monsters (TCoE p. 148), and the charmed condition.