Access to portal without password?

Access to portal without password?

I'm testing the customer's portal features and actually there is something that I think it's not so useful to the customers. My point is: each time a new contact or account is added to Zoho Invoice I have to authorize them manually to access the portal? Can't we "bypass" the authentication and leave customers to log into portal without having to input a password?

Why I'm asking that: when we send a new estimate to customer, on the email template we have a url that takes the customer to the portal, and after customer access that url for the 1st time, they will get "scared" about having to insert a password. I created on my custom template a button for the %EstimateUrl% variable and says this: "Click here to preview your estimate". So, it could sounds like weird visit that url and have to input a password which we actually don't know what its purpose. I don't know if I was clear in my explanation.

Thanks for helping.