The short answer
It depends where you are and what else you do. In some countries and some states or councils a licence or registration applies to grooming, or to the boarding and day care many salons offer alongside it. Where one applies to you, display it. Where none applies, display the things that stand in its place: training, insurance, first aid and experience.
This is orientation, not legal advice. Your local authority or regulator is the source of truth for what applies to your salon.
Why it varies so much
Animal businesses are regulated locally rather than globally. The activity that triggers a licence in one country is unregulated in the next, and the boundary usually falls around whether animals stay overnight, whether they are in your care unsupervised for extended periods, or whether you are breeding or selling them.
Grooming, where a dog is with you for a couple of hours and goes home the same day, often sits outside the schemes that cover boarding and day care. The moment a salon adds day care, home boarding, overnight stays or puppy sales, the position usually changes. If that is you, check before you advertise the service, not after.
There are also places with their own registration, inspection or premises requirements for grooming specifically, and places where none of it applies. Ask your local council, city or state authority what covers your address, and ask in writing.
Display it where you have one
If a licence, registration or inspection rating applies to you, put it on the site and be specific: the issuing authority, the number, the activity it covers, and any rating or expiry. Vagueness looks worse than silence.
The right places are a trust strip on the home page, the about or salon page in full, the footer as a line, and the first-groom page where a nervous owner is already reading. Diary a reminder to update it before it expires, because a lapsed number on a live website is worse than no number.
What to show when no licence applies
Most owners are not really asking about licensing. They are asking whether you know what you are doing with their dog. Where there is nothing to display, show the substance instead.
Qualifications. Your grooming training and awarding body, and any advanced or breed-specific qualifications, named properly.
Insurance. Public liability and cover for animals in your care, custody and control. Say you hold it. Owners rarely ask and are always reassured.
Canine first aid. Certified, with the date. Say who on the team holds it.
Membership. Any professional or trade body you belong to, at your actual membership level.
Experience. How long you have been grooming, and what you specialise in, whether that is hand stripping, doodle coats, cats or anxious dogs.
Reviews. Google reviews visible on the site, since owners weigh them heavily for anything involving their animal.
What never to imply
Do not use words like registered, licensed, approved or certified unless you can name the scheme and the body behind them. Do not display a badge for a membership you have lapsed, or a rating from an inspection that has since been repeated.
Advertising claims about animal health and treatment are also more tightly controlled than most salon owners expect in several countries, so be careful with anything that sounds like a veterinary or medical claim. Describe a medicated shampoo service as what it is and leave the diagnosis to vets.
Keep the country pages doing the work
Where a business serves more than one country, or where the same site is read across borders, the sensible pattern is to state your own credentials factually on the salon page and let country-specific pages carry the regulatory detail. Animal welfare licensing, boarding rules and veterinary advertising rules differ enough that a single generic page will be wrong somewhere.
Build it so you can edit it
Licence numbers, expiry dates, insurance renewals and first aid certificates all change. Build these as editable fields rather than text baked into a page template, so a renewal is a two-minute edit and the site never claims something out of date. Put the annual renewal and the site update in the same calendar reminder.
Where this sits
Displaying licensing where it applies, alongside training, insurance and first aid where it does not, is part of a dog grooming salon website as we build it, and the same trust pattern runs through our other pet business websites, with country pages carrying what differs by jurisdiction. The packages are on pricing. Say what you actually hold, keep it current, and let it sit where a worried owner is already reading.