Import Root CA / HTTPSi Certificate to Chrome
Open Settings > Privacy and Security > Manage Certificates
Press Import… and select the exported SSL CA file.
Import Root CA / HTTPSi Certificate to Firefox
Setting the "security.enterprise_roots.enabled" preference to true in about:config will enable the Windows and MacOS enterprise root support.
Enter “about:config” in the address bar and continue to the list of preferences.
Set the preference "security.enterprise_roots.enabled" to true.
Firefox will inspect the HKLM\SOFTWARE\Microsoft\SystemCertificates registry location (corresponding to the API flag CERT_SYSTEM_STORE_LOCAL_MACHINE) for CAs that are trusted to issue certificates for TLS web server authentication. Any such CAs will be imported and trusted by Firefox, although they may not appear in Firefox's certificate manager. Administration of these CAs should occur using built-in Windows tools or other 3rd party utilities.
Import Root CA / HTTPSi Certificate to Windows Certificate Store / Edge Browser
Installing a trusted root certificate
On the machine that requires a certificate, in your web browser, navigate to your local certification server. This should be the same certificate of authority used for generating the server and, optionally, client certificates.
Choose Download a CA certificate, certificate chain, or CRL link, as needed.
Select the appropriate certificate of authority from the list and choose the Base 64 Encoding method.
Choose the Download CA certificate link and then choose Open option when prompted to open or save the certificate.
When the certificate window opens, choose Install Certificate…. The Certificate Import wizard appears.
In the wizard, choose Next. Then, when you are prompted for the Certificate Store, choose Place all certificates in the following store. Select the Trusted Root Certification Authorities store.
Complete the remaining steps of the wizard and click Finish.
Upon completing the wizard, you next want to add the certificate snap-ins using the Microsoft Management Console (MMC).
Adding certificate snap-ins
Launch MMC (mmc.exe).
Choose File > Add/Remove Snap-ins.
Choose Certificates, then choose Add.
Choose My user account.
Choose Add again and this time select Computer Account.
Move the new certificate from the Certificates-Current User > Trusted Root Certification Authorities into Certificates (Local Computer) > Trusted Root Certification Authorities.