It's a 35 year-old price-point step-through "mountain bike" being ridden as a commuter. Maintain it, ride it, enjoy it, or buy a new bike. There is nothing worth upgrading here.It already has a nice saddle.
But I'd be concerned about the stem being raised past its safe insertion mark. If it is, lower it. If it isn't invest in longer cables for the shifters and rear brake.