Split infinitive

The infinitive in English is made up of two words: to +  the verb

To go, to see, to ask. If you are asked what the infinitive is, you reply using both words.

Some people labor under the illusion that the infinitive should not be split. They believe that to place any word (an adverb) between the to and the verb is a sacrilege.

They therefore object to a phrase such as To boldly go where no man has gone before or To gently rock back and forth.

They are wrong but, here's the thing, they will be the very people reading your first  job application. So when writing a formal letter, try not to split your infinitives. When writing for me, relax.

That said, try not to split your infinitive with the adverb not. The negative of to go is not to go;  the negative of to be gone is not to be gone.  So, He asked me not to make so much noise is correct, whereas He asked me to not make much noise is, well, iffy at best, although we may use it in conversation.

The infinitive also exists without to. In this case it is called the null infinitive. You will find it after modal verbs. You just did (will + find). You may also find it after the verb to help:  He helped me get home - or, if you prefer, He helped me to get home.