How to create a redirect for portal url?

You can create a URL redirect in Shopify admin. 

You can redirect yourstore.com/partners to your portal link.

Here are the steps:

1. From your Shopify admin, go to Online Store > Navigation.

2. Click URL Redirects.

3. Click Add URL redirect.

4. In Redirect from, enter the URL that you want to redirect visitors from. For example /partners.

5. In Redirect to, enter the new URL that you want to redirect visitors to. For example /apps/convertout/home for your portal.

6. Click add. 

To learn more check out Shopify's help document on redirecting URLs:

https://help.shopify.com/en/manual/online-store/menus-and-links/url-redirect