I have an Apple Watch series 4 that I didn’t initially add cellular data too. How can I now add data? I have Verizon, latest iOS and I know there is a charge. There is no “cellular” option on my watch app

According to: Set up cellular on your Apple Watch - Apple Support

Here's what you need

• "Apple Watch Series 4 (GPS + Cellular) or Apple Watch Series 3 (GPS + Cellular) with the latest version of watchOS
• iPhone 6 or later with the latest version of iOS
• An eligible cellular service plan with a supported carrier
• Your iPhone and Apple Watch must use the same carrier
• You must be within your carrier's network

Before you set up cellular, check for updates to your carrier settings.

If you have an enterprise or corporate cellular service plan, check with your company or carrier to see if they support this feature. Pre-paid accounts and some older accounts aren’t currently supported. To make sure that your account is eligible, contact your carrier."