How do I address one label to and from?

If you put both the sender (to) and receiver (from) on the same address label, your mail won't be delivered.

Unless you have a label that fits the entire package or envelop and the return address label is located in the upper left corner and the receive is properly located in the center of the package. I'm unaware of address label like this, but it could be custom made from multiple companies.

You can upload spreadsheets to various websites to be printed or you can print addresses from home for your recipient addresses (to whom will receive the letter or package). Several programs allow you to upload recipient addresses from a spreadsheet.

You can search for mail list merge on google for specifics on doing this at home.

The return address label is the label from the sender (located in upper right corner of the envelope or package).