If you are going to be accepting or processing secure information from your website, such as credit card payments online, or other sensitive information, you will need an SSL certificate. SSL stands for Secure Socket Layer. Data shared between users’ computers and the server are encrypted for safety.
There are different grades of SSL certificates. Price ranges from very little money, to hundreds of dollars per year. The more sensitive your information, the more you’ll probably need to spend on an SSL certificate.
Most applications can get by with certificates costing less than $100 per year. If you are accepting Credit Card payments directly from the server, you will need to contact your bank or credit card payment gateway to determine their requirements. Some are quite strict.
Your server needs to have capability for secure connections. This is probably nothing to worry about because most do.
You will need a dedicated (unique) IP address. If you are on shared hosting plan, you will need to ask your hosting company for a dedicated IP address. SSL certificates cannot be installed on a shared IP unless the certificate is shared. That is not a common scenario at all.
Some hosting companies will move you to a dedicated IP address for free. Others charge a (usually) tiny monthly fee for a dedicated IP address.
You will need to generate a Certificate Signing Request (CSR). If you’ve never had an SSL certificate on your site, you may have to generate a “Key” first. These are both done from your server’s control panel.
If you’ve done everything correctly, it should install without problems. If you receive errors or warnings, you may have to contact your server administrator for help.