Q: Can I access wifi through my cellular connection on my iPhone 6S if there is no wireless system available? My husband's Samsung cell phone can access wifi through his cellular connection.

You can access the internet using your cellular data. You can turn that option on (if it isn't already) by opening Settings and then tap on Cellular and turn Cellular Data to on (green). You can leave that on if you want and your phone will automatically use wi-fi if it is available and cellular data when wi-fi is not available. Note that you must have a cellular data plan with your carrier and that using more cellular data than your plan allows may incur extra charges.

The following may help: If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network - Apple Support

See the information below from If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network - Apple Support

If it can’t connect to any Wi-Fi networks, contact Apple.