just (do something)

You use this phrase when the action you're describing seems easy, simple, fast, unimportant, or unexciting:

I just googled "new york florist" and that was the first shop that came up, so I called them.

A: What did you do this weekend?

B: I just sat at home and watched T.V.

I'll need to (do something)

This is a polite, formal way to talk about something that you have to do, or to ask for something. People in customer service jobs often speak this way. 

Here are some examples:

I'll need to check your I.D., sir.

I'll need to check with my manager. Please hold a moment.

You can also say "I'll need you to ____":

I'll need you to verify your address, please.

I'll need you to sign right here.

When you're not speaking as politely or formally, you can drop "will":

I need to see your I.D.

a photo I.D.

A "photo I.D." is an identification card that has your photograph printed on it. A passport and a driver's license are examples of a photo I.D.

You may be asked for a photo I.D. when you're doing something like:

• applying for a loan at a bank
• paying for something expensive with a check or credit card
• checking in at an airport