I've downloaded Electrum and have successfully transferred my first small amount of bitcoin to my wallet (after purchasing some through an exchange). I used the receiving address (by copy pasting it to the exchange) but what are the other options in Electrum's receive tab for 'description' 'requested amount' 'request expires'? In what circumstances should I fill in these fields... and in what circumstances should I save or create a new address? Thanks for your help, (I've searched online but doesn't seem to be a lot of information on these type of details)
Those fields are encoded into the QR code, so that it is easy for the person to pay you. The payer just scans the QR code, and if their wallet knows how to read BIP21 URIs, then they will already have the amount, description, and address filled into their payment form. In addition, if the offer is only available for a limited time, the wallet will prevent/warn the user from completing the transaction.
Actually if possible, create a new address for each transfer... For businesses or ppl who like to receive bitcoins with their online shop for example may not have the luxury of creating a new address for each payment they receive, but if you care about staying anonymous, you create a new address each payment ;)