Two alternatives for typing:
1. To type in Gurmukhi, install Google Input Tools; under options select and use the first Punjabi (ਪੰਜਾਬੀ) option -- one with ਅ icon. This will convert the English characters into the closest phonetic equivalents in Punjabi. https://chrome.google.com/webstore/detail/google-input-tools/mclkkofklkfljcocdinagocijmpgbhab?hl=en
2. Memorize the Romanized pronunciation given along with each word and type that approximate Romanized form when asked for writing in Punjabi.