For Zoho QEngine to perform iOS testing, an application will be installed on the test devices. To ensure secure installation and execution, Apple requires apps to be code-signed and linked to a provisioning profile.
A code signing certificate verifies that the application installed comes from a trusted source and hasn’t been altered, while the provisioning profile authorizes the app to run on registered devices and access necessary app services.
To set up iOS testing, you’ll need a Mac and an Apple Developer Account. The Mac used must be the same machine where testing takes place.
2.1 Generate a Code Signing Certificate
Create a Certificate Signing Request (CSR)
Open the default Keychain Access app on your Mac.
In the top menu, go to Keychain Access > Certificate Assistant > Request a Certificate from a Certificate Authority.
Enter the following details:

Provide your Apple Developer account email as the User Email Address.
Enter a Common Name. It's recommended to use a descriptive name, such as John Doe Developer Certificate
Select Saved to disk in the Request is field. CA Email Address field can be left empty, as it isn't required for this type of request.
Click Continue and save the .certSigningRequest file to your mac.
Generate the Certificate in Apple Developer Account
Go to Certificates, IDs & Profiles.

Under Certificates, click the (+) add button.

Choose the type of certificate according to your needs. Click Continue.
Choose a file and upload the .certSigningRequest (CSR) file you created earlier using your keychain manager app. If you haven't generated a request yet, refer to the Create a Certificate Signing Request (CSR) section. 
Click Continue, then Download the .cer file.
To install the certificate in your keychain, double-click the downloaded certificate file. The certificate appears in the My Certificates category in Keychain Access.
2.2 Create a Provisioning Profile
Register your App ID
In your Apple Developer account, go to Certificates, IDs & Profiles.
Under Identifiers, click (+) to create a new App ID.

Select App IDs from the list of options and click Continue.
From the options, confirm App as a type, then click Continue.
Enter a name or description for the App ID in the Description field. This description will be used to identify the App ID while creating the provisioning profile. Learn more
Define a wildcard App ID, select Wildcard, and enter a bundle ID suffix in the Bundle ID field. (For example, com.* )

Click Continue, review the registration information, then click Register.
Register Devices
You need one or more registered devices to create a provisioning profile. If you have many test devices, you can create a file containing the device names, device IDs, and platform, and upload the entire file to your developer account. Learn more
Note: If your devices are already registered, ensure they are selected when generating the provisioning profile.In Certificates, Identifiers & Profiles, click Devices in the sidebar, then click the add button (+) on the top left.

Select the platform, enter a device name, and the Unique Device Identifier (UDID). Click Continue.
Review the registration information, then click Register.

Note: For more details on disabling and restoring devices in your Apple Developer account, refer to this guide
Generate the Provisioning Profile
In Certificates, Identifiers & Profiles, click Profiles in the sidebar, then click the add button (+) in the top-left corner.
Under Development, select the type of provisioning profile you want to create, then click Continue.
Select the App ID you created. You can identify it by the description you entered during the App ID creation step. Once selected, click Continue.

Select the code signing certificate you created earlier, then click Continue.
Select the registered devices to be included in the provisioning profile.
Enter a Provisioning Profile Name and click Generate.
Download the .mobileprovision file.
To complete the setup, save the code signing certificate and provisioning profile in the Zoho QEngine dependency folder on your machine. This ensures that Zoho QEngine can access these files during test execution.