Could you rephrase that in English please?

I would like to integrate sogo into another portal and I would like the user not to have
That to insert the user and the password again since previously it has
Introduced and has been authenticated using LDAP. Is there any way to do it?

There is SAML2 authentication in SOGo. With that you could do SSO (= single sign on).
One variant is e.g. Shibboleth that does this.
But you would need to change your portal, in order to use SAML2 too.
And you would need some sort of central authentication server which generates the SAML2 session.

If your users use KeePass as password manager, they could use KeeFox extension in Firefox, in o?der to get at least auto filled fields.