Hey there! There are a bunch of options. It really depends on how fast you want to do it/money/location.

Depending on where you live there should be a university/college offering a design degree or a visual communications degree you can do. These can take years though and for me personally I tried it and hated the course structure and method of going to random tutorials in different places. 

There are always the private college providers but that means $$. I was lucky enough to attend one in Sydney and got some great training and it suited my ambitions and lifestyle.

There’s also TAFE (or whatever government funded tertiary provider you may have in your location) which is also great. It is probably the cheapest option and can take a year or 2.

At the end of the day all these avenues end up in a similar place, its more how you personally market yourself and display the work you have done. Also, unfortunately it can also come down to ‘who you know’ so talking to all your friends/family/co-workers about anyone they may know who might need a designer once you get some training is a must. Make yourself known to the right groups of people (post work online/contact design agencies etc). Do small jobs for friends or family to show some ‘real’ work to potential employers so you don’t go to an interview with only school work in your portfolio.

Usually wherever you get some training will also help you out with ways to market yourself or find some contacts. Unless you are in Australia I can’t really help you with specific courses/providers so I hope my vaguely long answer helps in some way!