Have you checked the docs?
Update the phone column
In JavaScript, with a simple string:
To update a phone column, send “+”, the phone number, and the ISO-2 country code (capitalized) as a string. Make sure to capitalize the country code and separate it from the phone number with a space to avoid errors!
fetch ("https://api.monday.com/v2", {
method: 'post',
headers: {
'Content-Type': 'application/json',
'Authorization' : 'YOUR_API_KEY_HERE'
},
body: JSON.stringify({
query : "mutation ($myBoardId:Int!, $myItemId:Int!, $myColumnValue: String!, $columnId: String!) { change_simple_column_value (item_id:$myItemId, board_id:$myBoardId, column_id: $columnId, value: $myColumnValue) { id } }",
variables : JSON.stringify({
myBoardId: 1234567890,
myItemId: 9876543210,
columnId: "phone",
myColumnValue: "+19175998722 US"
})
})
})
In JavaScript, with JSON:
To update a phone column using JSON, send “+”, the phone number for the phone
key, and the ISO-2 country code (capitalized) for the countryShortName
key. Make sure to capitalize the country code to avoid errors!
fetch ("https://api.monday.com/v2", {
method: 'post',
headers: {
'Content-Type': 'application/json',
'Authorization' : 'YOUR_API_KEY_HERE'
},
body: JSON.stringify({
query : "mutation ($myBoardId:Int!, $myItemId:Int!, $myColumnValues:JSON!) { change_multiple_column_values(item_id:$myItemId, board_id:$myBoardId, column_values: $myColumnValues) { id }}",
variables : JSON.stringify({
myBoardId: 1234567890,
myItemId: 9876543210,
myColumnValues: "{\"phone\" : {\"phone\" : \"+12025550169\", \"countryShortName\" : \"US\"}}"
})
})
})
Or I’d probably go with:
fetch ("https://api.monday.com/v2", {
method: 'post',
headers: {
'Content-Type': 'application/json',
'Authorization' : 'YOUR_API_KEY_HERE'
},
body: JSON.stringify({
query : "mutation ($myBoardId:Int!, $myItemId:Int!, $myColumnValues:JSON!) { change_multiple_column_values(item_id:$myItemId, board_id:$myBoardId, column_values: $myColumnValues) { id }}",
variables : JSON.stringify({
myBoardId: 1234567890,
myItemId: 9876543210,
myColumnValues: JSON.stringify({
"phone": {
"phone": "+12025550169",
"countryShortName": "US"
}
})
})
})
})
These examples give actual real values that are valid, so please make sure you have valid input and reply with the definitive answer for PHP 