El Extranjero

The word mi, which you used as a translation of the English 'my', needs to agree in number with the word that it modifies. Since 'palabras' is plural, 'mis' should be used.

So, what you should have written is:
Por favor, corrijan mis palabras y vocabulario.

(The Eastern Hemisphere version is:
Por favor, corregid mis palabras y vocabulario.)


Let's say you wanted to address one person. The singular second-person form would be used with friends (associated with tú). But if you wanted to show respect to the individual you're asking, you would use the third-person singular form (associated with 'usted').

So, in addition to the two forms given above, there are two more you could have said:
Por favor, corrige mis palabras y vocabulario.
Por favor, corrija mis palabras y vocabulario.

It all depends on your audience!
In English, the command is 'correct', no matter who the audience is.

The first step to consider when conjugating a verb is what mood to use. You were asking for a correction, so that means you'll use the imperative mood.
The next step is to determine the person. There are three, each with a singular and plural form. Since your command is probably meant for more than one person, the plural form should be used. You don't want to say "let's correct," so move on to the other plural forms. The second-person plural is only used in Spain. If you live in the Western Hemisphere, you should use the third-person plural. That is 'corrijan'. You can look this up yourself in a verb chart. This is the imperativo associated with the third-person plural (ustedes). In Spain, use the second-person plural (associated with vosotros).

I'm pretty certain that 'Por favor,' is what you meant to type at the beginning of your sentence. A sentence always starts with a word that has a capital letter. A sentence always end with a period (called a 'full stop' in BrE).

Your third word means 'correct', but it's an adjective. What you were meaning to use is the action of correcting something, so you'll need to use the verb 'correct', instead of the adjective. When you look in a dictionary for verbs, you'll find them listed in the infinitive form. The infinitive for 'correct' is corregir. You can't use 'corregir' as a verb. You must conjugate it.

por pavor correcto mi palabras y vocabulario