Please (do something).

Writing "Please ___" is a formal way to ask a question. You can use "Please ___":

• for very important requests
• when you are angry at someone and don't want to be too friendly with them
• when you're writing to someone who you don't know
• when you're writing or making an announcement to a group of people

For a friendlier, but still very polite, way to make a request, you can write:

If you could get back to me by the end of the day, that would be appreciated.

notify (someone) of (something)

To "notify" someone of something just means to tell them. You "notify" people of things that are new and that the person might need to know or might find interesting.

The word "notify" is more formal than just "tell" and is often used in business situations. Here's another example. When writing an e-mail to a client, you can offer to help when they have problems by saying:

Please notify me of any problems or questions that come up.

extensions

An "extension" is extra time that someone gives you after a deadline to finish something. So the "extensions sheet" is probably a document where people record when things can be finished that are going to go past the usual deadline.

This is a reminder to (do something)

When you want to remind people to do something, you can use the phrase "This is a reminder to ___":

This is a reminder to please fill out your time sheets by end-of-day Thursday.

You can also add the word "polite" to make your announcement sound less bossy:

This is a polite reminder to clean out the break room refrigerator at the end of the day each day. Please do not leave personal items overnight.

This phrase is formal, so you should use it when writing an email or making an announcement to a group of people. When you're talking to someone one-on-one, it's friendlier to say something like:

Hey, don't forget to fill out your time sheet by Thursday.

update (a document)

"Updating" a document means changing it in some way.

I updated my website with some new photos.

Things that you can "update" include:

• a website
• a résumé / CV
• a report
• a spreadsheet

a spreadsheet

A "spreadsheet" is a kind of document that people use for entering numbers and making calculations. Spreadsheets have rows and columns.

The most popular programs for spreadsheets are Microsoft Excel and Google Sheets.