Put the menu on a real web page
A PDF menu feels like the easy option. You already have the file, so you upload it and move on. On a phone, though, it means pinching and zooming around a document designed for A4 paper. Search engines find it harder to read too.
Publish the menu as a normal page with dishes and prices, and keep it current. If you like having the PDF, offer it as a download underneath.
Opening hours everywhere
Your hours should be on every page, at least in the footer. Update them for holidays before the holiday, not after. Turning up to a closed restaurant because the website said it was open is the kind of thing people remember.
Make booking one tap
If you take reservations online, the "Book a table" button should go straight to your booking system. If you'd rather take bookings by phone, make the number tap-to-call and put it near the top. For takeaway or delivery, link to your own ordering page or the delivery apps you actually use.
Help people find you
Give the address, a map and a line about parking. If you're tucked inside a mall or down a side street, describe it. "First floor, next to the pharmacy" helps more than a pin on a map.
Allergens and the rules that apply
Clear labels for vegetarian, vegan and gluten-free dishes help everyone. In some places the rules go further.
In the UK and EU, if customers can order online for delivery or collection, mandatory allergen information has to be available before they complete the order and again when the food arrives. In the US, chains with 20 or more locations must show calorie information, including on online menus. In Saudi Arabia, the SFDA requires calorie information on restaurant and café menus. Rules change, so check the current ones where you trade. This isn't legal advice.
Photos that don't slow things down
Good food photography sells. Huge photo files, on the other hand, make the page crawl on mobile data, and a hungry person won't wait for it. Resize photos for the screen and save them as WebP, and you get both. There's more on this in why is my website slow?
The smaller things on my restaurant website checklist
Say what kind of food you serve and roughly what it costs, so nobody is surprised at the table. Mention private dining or catering if you offer them. Link to your Google Business Profile so reviews and directions are one tap away.
In the Gulf, guests often expect a menu in both English and Arabic. Do it properly, with the Arabic laid out right to left, rather than squeezed into the English design.
Finally, add Restaurant structured data with your menu link, cuisine, hours and price range. Visitors won't see it, but search engines will.
There's more on restaurant website design, or you can ask for a free homepage demo for your restaurant.