When do you use vosotros or ellos and what is the exact difference between these two?

Answer 1

Vosotros is the 2nd person plural

Ellos is 3rd person plural

The regional variation is on the 2nd person plural:

Vosotros is manly used in Spain

In other countries the form Ustedes is preferred and this form is conjugated using the same verb forms as the 3rd person plural.

Answer 2

Vosotros means "you all" and ellos means "they". The difference in usage is the same as English. Perhaps you meant to ask about the difference between vosotros and ustedes. Both are a plural form of you, i.e. you all. Vosotros is only used in Spain and is an informal plural, i.e. to be used in non-professional circumstances. Ustedes is the formal plural, i.e. to be used in professional circumstances. In Latin America, since vosotros is not used at all, ustedes simply becomes the form for any case of plural you.

Answer 3

In Spanish, "vosotros" is used for addressing a group of people in informal situations, mainly in Spain. On the other hand, "ellos" is used for referring to a group of people in a more general or formal context, regardless of being formal or familiar. The main difference between the two is formality and regional usage.