Use the Pre-request scripts (it's next to body) for this:
var encoded = encodeURIComponent({{phone number}}); or
var encoded = encodeURIComponent(postmanpm.getEnvironmentVariableenvironment.get("phone number")); and to proceed, use:
postmanpm.setEnvironmentVariableenvironment.set("encoded phone number", encoded); And set your URL to /path/get?phone={{encoded phone number}}