Is it possible to trade cargo and/or credits from one character I have to another? Example: can I mine and then transfer load to my transport character? And, can I earn credits and transfer to my other characters. Fyi: No interest in multi-box. Please don't suggest.
/givecash SHIPNAME AMOUNT is the command you're looking for. Unfortunately you'll need another person to help you with cargo transfers. That one's done via the trading function (button in left part, near HP/shield) and needs the other person in your vicinity (at less than 1k)
If you have discord, finding someone to help with a transfer is usually quick.
For transferring mined goods one alternative is selling them to a nearby pob. That is very ineffcient though which is why you see mining referred to as a multi person activity.
What I see most of players do is flying to a minable zone with the transport ship, disconnect in space. Wait one minute, reconnect with their miner ship, mine 5000 units of Ore, jettison everything and leave it in space. Disconnect from the miner, wait one minute, and reconnect with the transport. Tractor everything in space and off they go.