Can I modify field value 'programmatically' when constructing URL in custom button?

Can I modify field value 'programmatically' when constructing URL in custom button?

In the lead module, I save the phone number. Then I try to create a custom button so when our user click the button it will open the Whatsapp App in the Web Browser. to open the Whatsapp in the browser I have to open the URL using the format below

https://web.whatsapp.com/send?phone=(country_code)(actual number)

so the link will be something like this:
https://web.whatsapp.com/send?phone=628123456789

I am from Indonesia, the country code is 62. unfortunately in our country, people usually write their number using '0', so the number above will be saved as 08123456789 in my Phone field in Leads module.

I try to create custom button like this



as you can see I write the URL like this:
https://web.whatsapp.com/send?phone=${Leads.Phone}

but when press the button it actually will open this URL
https://web.whatsapp.com/send?phone=08123456789

it won't open Whatsapp because it has no country code in it. so basically I have to change
from 08123456789 to be 628123456789 . I have to change from 0 to be 62.

can I do that 'programmatically' ? I am a programmer, I can do it easily in Javascript, but I need to know how to do that in Zoho CRM