How to call the hotel in London with the smart phone

A + equals 00. Doesn’t matter what kind of phone you have. Even dumb phones dial this way.

Sorry still do not understand can you clarify please. + = 00
What about (0) what does that mean?

I don’t think you need the 0 after the 44.

https://www.howtocallabroad.com/uk/

Thanks

00 is me essay when in london?

When calling in London is it necessary to start with 00

If you have a British SIM in your phone, dial 020 77238575.
If you have a non-British SIM in your phone, dial +44 20 77238575.

https://www.ricksteves.com/travel-tips/phones-tech/call-uk-europe

Charlotte, to dial any number in the world you need:

[International access code] [country code] [area code] [number]

The [International accesscode] is the number you dial in order to get an international connection. It varies depending on the country you are dialling FROM. It is 00 from a landline in most countries, + from a mobile phone, something different from the USA
The [country code] for the UK is 44.
The [area code] for London is 020. But the first 0 is the national access code, you don't need the first 0 if you are dialling from a different country.

• From a smart phone of any nationality dial: + 44 20 7723 8575
• From a landline in a different European country dial 00 20 7723 8575
• From a landline in the UK dial 020 7723 8575
• From a Landline in London dial 7723 8575 (London has 8-digit numbers)

Just one addition to Chris's post.

From a land line in the US dial: 011 44 20 7723 8575

This has been helpful for me, can put the number in and it'll give you the thing to dial (it'll remove the 44 for the country code, and make it the way you need it, if you enter it the way it says to):

https://www.timeanddate.com/worldclock/dialing.html

They also have good clock converters, esp helpful since the daylight savings time here and there don't end on the same day, the 2+ weeks of differences happens around this time of year.