Anybody vs. Anyone

'Anyone'' and 'anybody' basically have the same meaning. They both mean 'any person'. Although they can be used interchangeably, they have subtle differences in their meanings.

'Anyone' is consisted of two parts: 'any' and 'one'. It is a singular word. It means any single person without differentiating one person from many.

In all the examples above, the speaker's intent is to find just one individual person, not a multitude of people.

'Anybody' is a plural word. It means any possible people. We use 'anybody' to address a group of several people.
In a context where we do not intend to find only one person, we want to address a group, for example:

In the examples above, we are trying to find any and all persons who can respond, any number of people, not only one single individual.

In a sentence where we have used indefinite pronouns like 'anyone' or 'anybody', and we do not know if the person is man or woman, we often use the plural pronoun 'they' to refer back to them.

'Anyone' and 'anybody' are not negative markers, i.e. they do not have a negative meaning on their own.

'Anyone' is a bit more formal than 'anybody'. 'Anyone' is used more in writing and more formal styles than 'anybody'.