an, and

An or an is an article, meaning it refers to any example of the same or a similar thing--not to a specific thing, as "the" does.
 "An" and "a" are the same word--with the same meaning and use-- "an" is used in front of a word beginning with a vowel (open-mouthed sound), since it is hard to hear or say "a" before this type of sound.
 "A" or "a" is used before a consonant ( closed-mouth  sound )--
I would like an apple.
Would you like a piece?
Can I have an orange?
Would you like a slice?

And or and  means in addition to, or plus--
I would like some apples and some oranges.
I am going to the store and to the bank.

Now that you know that, you can say--
"I would like an apple and a slice of  orange."

Not to be confused with Ann or Anne, a woman's or girl's given name.

Note--you may come across "en" in your reading. This refers to the letter "n", sometimes used to specify the length of a typed or printed "dash" ( - ) .
An "m" dash --
An "n" dash -