Sell bitcoin to account So let's say I have multiple bitcoin addresses (some of them already received bitcoins), created a new bitcoin address, received bitcoins on it and would like to use the very same address to send them elsewhere - how can I do that?
Most wallets don't pay attention to which addresses you "send from", and for most purposes it doesn't matter.  When you try to send coins, they will select inputs from among all the transactions paid to all your addresses, hopefully in such a way as to minimize your transaction fees in the long run.

However, some wallets, such as Bitcoin Core, have a "coin control" feature that lets you manually select the inputs for a new outgoing transaction.  You could use this to choose only inputs that come from your desired address.  But in most cases there isn't any need to do this.