Conjunctions (a part of speech) are words used to link words, phrases, and clauses.
For example, I ate the pizza and the pasta.
In this case, ‘and’ is a conjunction that joins two parts of the sentence.
There are three types of conjunctions and these are discussed below:

You use co-coordinating conjunction (and, but, or, nor, for, so, yet) to join individual words, phrases, and independent clauses that are grammatically equal.
Example: Lilacs and violets are usually purple
There are seven main coordinating conjunctions:-
For, And, Nor, But, Or, Yet, Soon
These conjunctions are arranged in this way to provide the mnemonic acronym of FANBOYS so that it is easy to remember them.
Note: One can also use the conjunctions “but” and “for” as prepositions.

A subordinating conjunction introduces a dependent clause and indicates the nature of the relationship between the independent clause(s) and the dependent clause(s). The subordinating conjunction always comes before the dependent clause but the dependent clause itself can be placed either ahead of or following the independent clause.
Example: Since they had misbehaved, the boys were given a one-week suspension from the school.
Other subordinating conjunctions are – Although, As, Before, Once, Though, Until, Whether, etc.

Correlative Conjunctions are simply pairs of conjunctions used in a sentence to join different words or groups of words in a sentence together. Correlative Conjunctions are generally not used to link sentences themselves, instead, they link two or more words of equal importance within the sentence itself.
Examples: Both the shoes and the dress were completely overpriced.
Just as she loves the hiking so she enjoys traveling as well.