Which jobs are regulated, and by whom, differs by country and by province or state. This explains the three categories and how to find out which one your job is in. It cannot tell you the answer for your job in your place. The check it describes is free, and the body that answers it is public.
Regulated. Certified. Neither.
People spend real money on the wrong one, because nobody explains that they are different things.
A body decides by law who may practise. Without their permission, doing the work is illegal — not merely unwise.
A qualification that says you meet a standard. Useful, sometimes expected by employers, but not a legal gate.
You can do the work without it.
Most jobs. No licence, no standard body, whatever the employer will accept.
Which is why job adverts asking for certification can be misread as a legal requirement.
Which kind is each, in most places?
Tap an item, then a bucket
What is the commonest costly mistake here?
In many countries regulation sits with provinces or states, not the national government.
So a licence can be valid in one region and worth nothing next door.
Moving between regions of the same country can mean re-licensing, and moving between countries usually does.
The qualification travels. The permission often does not.
Find the regulator for that occupation in that place and read their own page.
Not a school, not an agency, not a forum. The body that grants the permission.
Colleges sell courses. Agencies sell placement. Both will answer the question in a way that suits them, sometimes without meaning to.
The regulator has nothing to sell you.
The exact requirements, what they cost, how long they take, and whether your existing qualifications count.
That last one is the question most worth asking before spending anything.
Regulated means you legally cannot without permission. Certified means somebody vouches for you. Neither means it is up to the employer. Find the regulator, not a course.