how to force guest customer to register member account in my webstore?

[maria_skula1]

Hello, @wade_wilson1 I personally wouldn't recommend you to force your users to create a customer account. Since nowadays people are scared off by long registration process and sharing some personal data it is likely they will just leave your website when forced to create an account. 
What I recommend you is to allow the checkout and still create a great customer experience. There is  this awesome module, Magento 2 Convert Guest to Customer extension by Magefan, which allows you to convert guest order to customer account as well as:

• to set the process of conversion to be automatic, so that every time user places an order as guest there will be automatically created an account;
• to assign order address to customer;
• to convert all old guest orders to customers in one click;
• to change order customer;
• to assign a newly created customer to a certain customer group.

[lilly_wilson]

Hi,

To force guest customers to register member account in your webstore, I recommend this extension Magento 2 Force Login. Magento 2 Force Login/Required Login allows store owners to hide store content and ask customers to log in if they want to access and view the detail page. Customers are restricted to access certains pages and will be redirected to another page after logging in.

Prominent Features:
- Restrict non-logged-in customer access
- Enable ''Force Login'' on specific or all pages
- Apply Required Login to default pages
- Apply Required Login to CMS pages
- Apply Required Login to custom pages
- Required Login with custom pages including strings
- Required Login with custom pages excluding strings
- Set destination page after customers log in
- Redirect customers to targeted page after logging in
- Display required-login notice on configured page
- Allow/disable visitors to create customer accounts
- Quickly enable/disable Required Login
- Manage backlist page - Force Customer Login overview
- Compatible with Magento 2.3.x CE & EE
- Available for B2B

[Mark2669]

Hi @wade_wilson1 

You can use Hide Product Price Magento 2 Extension to hide product price and Add to Cart button from non-registered customers. To see the price of a product, a customer must register and login to your store. This module encourages customers to register in your store.

Key Features:

• Easy To Install & Manage
• Enable/Disable From Backend
• Hide Individual Product Price
• Redirect To Custom URL
• Login Popup
• Set Hide Price Time
• Ability To Set Custom Message
• Increase Customers
• Hide Add To Cart