In my previous home I had an Hibiscus which I grew from a 3ft 'twig' - it was totally bare. I pruned it every spring or around Feb/March to be more precise. It used to grow lots of new branches and in the end (about 8 years) it stood 8ft Tall. It was fabulous and if could have moved it with us I would have.
This article should answer your questions: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/tips-for-pruning-hibiscus-plants-when-to-prune-hibiscus.htm