how can I use my HP Laser Jet 1020 Plus printer on my Macbook air

As Gail said, it's an old (though venerable) printer which is no longer supported nor has it been for a long time - I think 4-5 years. I was able to continue using it for a period of time because I continued to use an older OS on a computer and used printer sharing. If I recall properly it was Snow Leopard or Lion that I was running.

Hi, RajanGB !

About the only option left to you (assuming you can hard-wire the HP to your wireless router) would be to install and use Gutenprint. There is no guarantee this will work, so the only reason I bring it up is the sense we are deep into Hail Mary territory here. If you are desperate enough to give Gutenprint a go, it may serve your needs.

I hope this helps, and good luck !

The LaserJet 1020 is over 10 years old. If HP is no longer providing driver software, then there is not a lot you can do about that. It is unfortunately so old that it also probably does not support AirPrint:

About AirPrint - Apple Support

Best,

GB