Are all words supposed to start with capital letters...

[TanselleTooTall]

...when writing something like a menu or price plan?

Example being:

Oven Clean - £40 £25 Extra For Double Sized Ovens.
Hair Highlights - £60 £15 - £25 Extra For Very Thick Or Waist Length Hair.

I couldn't think no of very good examples, but I hope you get the gist of what I am asking.

Thanks in advance.

I would capitalise Oven Clean and Hair Highlights, but punctuate the descriptive sentences normally.

I thought so, too.

Signs, menus, ads etc are all clearer written with caps and lowercase. That’s why road signage is usually mostly lowercase.

I’d just capitalise the first letter, if necessary. But in lists that follow a heading I wouldn’t use caps at all except for proper nouns.

There are other ways to make the item stand out - type size, bold etc.

No, as they aren't proper nouns. Capital letters tend to be over used in writing, so it you will see it like your examples.

Capitalising all words might be done in titles. It can make it difficult for some people to read it, so generally best avoided especially if it's information you want accessible to all.

Thank you.

Unless they are headings, lower case is correct - eg

Oven Cleaning
Basic clean £10
Standard clean £20
Extra clean £30

So in other words your example is easier to read as:

Oven clean - £40 (£25 extra for double sized ovens)

Hair highlights - £60 (£15 - £25 extra for very thick or waist length hair)

It's very much a stylistic choice. Do whatever looks best in the typeface and arrangement you have. All caps, tall+small caps, all lower case are also possibilities.

If you're doing things like wall menus and table menus, you don't have to be consistent - using good looking styling for small handheld lists or large signs on the other can look dreadful.

The "all capitalised" you have above looks pretty old fashioned, but that may be the look you're going for.

Get a bit more separation between the primary price and the variants, so as to be extremely clear and avoid arguments:

Hair Highlights - £60 (£15 - £25 extra for very thick or waist length hair)

Hair Highlights - £60 ~~~ £15 - £25 extra for very thick or waist length hair)

Hair Highlights - £60 £15 - £25 extra for very thick or waist length hair

Hair Highlights - £60
£15 - £25 extra for very thick or waist length hair

and so on.

Also (seeing I'm on a roll 😁) all-caps, italics and underlining all make reading the text harder to read for some people.

As does justified text (where the text is aligned to both left and right margins).

I'll stop now!

'make reading the text harder to read.'

Oh dear 🤣

Hopefully you understand what I mean!!

Omg no.

Main words only, as others have said.

Thank you.
I have to check homework and the way it has been written made me pause to think!

Oh, homework checking? Well, depends mostly on the teacher I guess.

If your kid wants to use lots of caps, get them to look up "title case" - there are useful standards for these things.

Ooh thanks, very helpful.