Generate an iOS signing certificate Learn how to generate the .p12 file used for signing your iOS app. Signing certificates are required for Xcode. Generate .certSigningRequest file On your macOS device, launch Keychain Access. From the Keychain Access menu, choose Certificate Assistant, then select Request a Certificate From a Certification Authority. Enter your email and name, but leave CA Email Address blank. Then choose Save to disk and select Continue. Select Save to download your .certSigningRequest file. Generate .cert file Open Apple Developer, select Certificate, Identifiers and Profiles, then Create new certificate. Choose Apple Development, then select Continue. Select Choose File, choose the .certSigningRequest file, then select Continue. Select Download to download your .cert file. Generate .p12 file On your macOS device, launch Keychain Access. Select Certificates, then drag and drop your .cert file into the Certificates page. Right-click your .cert file, then select Export <your-cert-file>. Choose the Personal Information Exchange (. p12) file format, then select Save. Add .p12 file to Xcode project Launch Xcode and select your project. In the project menu, select Signing & Capabilities. Choose Signing (Debug) or Signing (Release). In the Signing Certificate dropdown, select Create. Choose Import an existing Certificate. Select your .p12 file.