Welding Tips and Tricks

Hello everyone!
I'll be purchasing a welding machine soon. I am currently using my dad's machine, which is not always convenient. Most likely it's going to be a fairly used device, , and I'd like to hear some advice on how to choose the right device. What to pay attention to when buying? What details to check and so on? I use the device specifically for work so I don't really understand its "internal" components.
I'd be grateful if I could get some advice.
Thank you!

The most important information will only come after you are more specific as to exactly what you want to weld with your welding machine. That will save everybody a lot of time and at the same time give you the most concise suggestions/advice. The needs of someone welding 4 to 6 foot diameter pipe using submerged arc welding are quite different from the needs of someone doing yard-art for a side-gig to make extra money in their spare time.

Welcome to the forum.

Or at least post a picture of the machine your borrowing. That will give a good reference of your needs compared to wants.