Yes, sir.

When you're speaking formally and politely, you can say "yes" to someone like this:

Yes, sir.

Yes ma'am.

"Yes, sir" or "Yes, ma'am" would be appropriate for:

a customer service employee talking to a customer

a polite high school student speaking to the principal of his or her school

a polite person speaking to a stranger

Can I just get (some information)?

When you want to get some information from a customer, you can ask for it this way:

Can I just get your name and phone number?

Can I just get the last 4 digits of your social security number?

Asking in this way makes your question sound quick and easy to answer.

order number

When you buy something that has to be mailed, emailed, or shipped, you usually get an invoice. An invoice is a document which shows details about your order. It may have various numbers or codes printed on it, including:

• an order number, which identifies your order
• an invoice number, which identifies the invoice itself
• a customer number, which identifies you
• a tracking code, which you can use to find out where your package is while it's being sent
• item numbers for each of the things that you bought

I can help you with that.

This is a set phrase that bank tellers, customer service representatives, and other workers that deal with customers use. When a customer asks for something, and you're able to do what they're asking for, you can respond:

Yes, I can help you with that. 

This sounds polite and a little formal.

(something) is printed on (an) invoice

An "invoice" is a document which records details about a sale. It lists information like:

• the business name
• each of the items that were bought or sold
• the number and cost of each item
• the total amount of the sale

You can talk about information that's printed on an invoice:

Can you read out the 5-digit code that's printed at the top of your invoice?