By default, when we purchase a Linode VPS, we only have one independent IP address. Maybe we need to add an independent IP address because of some needs. Generally, we can establish several websites for VPS, but if there are many websites, they are not friendly to the same IP address to some extent, and the websites have certain concerns. The minimum annual payment for Linode VPS is $19.95. If it is impossible to purchase another VPS for independent IP, we will purchase the IP separately. Independent IP is also very cheap, only $1/month.
First, we log in to the background of the linode VPS account and click the "Dashboard" panel in our space to manage;
Secondly, click "Extras" to expand purchase options;

Finally, we choose independent monthly or annual IP payment to submit the order.

After submitting, Lao Zuo found that it was difficult to place an order to purchase immediately. Instead, the prompt "Additional IPv4 addresses require technical justification. Please open a Support Ticket describing your requirement." appeared. It seems that the amount of IPv4 is not enough, and we need to contact TK separately to purchase. I'm going to apply now. I don't know whether I can pass.
Conclusion: After the application was submitted, the answers were relatively quick, which is the reason why I submitted the application for an independent IP. It seems that I will not approve the second independent IP unless SSL is used.