how to schedule a webhook with a date variable?

Hmm, what have you tried so far?  What service is the webhook on? 

Assuming you’re already familiar with how to set up your webhook, you could add an input variable like so for the current date time and then send it through?

The webhook is for Make, i need to send the record at 6AM at the specific date in one column of the record… I guess i have to make a formula, but neither airtable AI or gpt  give me a solution working...

Ah I see!  If this timing is set, i.e. it’s always at 6am, I’d recommend using the “At scheduled time” trigger

If each timing is dynamic based on the record, you’d need to use a formula field to trigger the automation:

IS_AFTER(
  NOW(),
  Date
)

The problem with this is that ‘NOW()’ doesn’t update immediately and has a lag time of 15 minutes to an hour or so, and so it wouldn’t be 100% accurate though

thanks, it can be 6h15 or even 6h30…. How do you send the webhook in the formula?

(in order to do something at a given time)
You should learn about Automations and how to create and use them. With trigger Airtable automation trigger: At scheduled time. and Airtable automation action: Run a script

(how to call a webhook)
Webhook is like a service operator in a Pizza House at a given number, that awaits when somebody calls and order pizza X on address Y.

in your case the phone number is some URL, which Make should provide
and the call is POST-request which Airtable should send to Make

Example of code to send a request with some data

this code must be inserted in a “Run script” automation step. 
input data usually taken as {variable1, variable2, variable3...}=input.config() in script start line , after you define variables in a left side of script editor. 
sometimes, when your input variables are the exact data to be sent, you can omit their names in code and directly assign a copy of input config to a variable containing data included in POST-request:  const payload={...input.config()}

const anyrec=query.records[0]
const oldvalue=anyrec.getCellValueAsString('STATUS')
const anyID=anyrec.id

//Send request
const hook='https://hooks.airtable.com/workflows/v1/gene..'
const payload={addtype,oldvalue,anyID}
const options={method:'POST', body: JSON.stringify(payload),
headers:{'Content-Type': 'application/json'}}
const responce=await fetch(hook,options);
const result=(responce.ok)? await responce.json() : responce.statusText;
console.log(result)

but in automations you can’t use a variable, wich sould be my date

Read  Step 3: Setting up input variables  of script step