To send out a request to receive funds, or to simply send your address to other people, you select "Copy" to copy the text and send it out, or you can tap on "Email" which will open your email and let you send it out to whoever you want to request money from. If they are right there with you, you can also simply let them Scan the QR code.
By default, the receiving Address will also automatically change for Bitcoin and other similar coins after each transaction or after each request email is made. This is done in order to increase your privacy. You may still continue to receive funds into any old addresses that have been used in the past.
Note that XRP Ripple, XMR, and Ethereum addresses do not change after each transaction.