You can use cloudflare, you have to register a free account at cloudflare and then use cloudflare name servers.  You have to use cloudflare name servers you cant just point an A record to cloudflare.

1. Registering at Cloudflare:

Visit Cloudflare: Go to https://www.cloudflare.com/ and click on the Sign Up link.

Enter Your Details: Fill in your email address and create a password. Follow the instructions to create an account.

Add Your Domain: Once you're registered, you'll be prompted to "Add a Site." Enter your domain name (e.g., mywebsite.com) and click Add Site.

2. Changing Name Servers to Use Cloudflare:

Scanning DNS Records: After adding your domain, Cloudflare will scan for your existing DNS records. This can take a minute or two.

Review DNS Records: Once the scan is complete, Cloudflare will display the DNS records it found. Verify that they match the current records with your existing DNS provider/host.

Get Cloudflare's Nameservers: After verifying the DNS records, you will be provided with two Cloudflare nameservers.

Update Nameservers at Your Registrar:

Login to your domain registrar's website (e.g., GoDaddy, Namecheap, etc.).

Navigate to your domain's management or DNS settings page.

Look for a section called "Nameservers" or similar.

Replace your existing nameservers with the ones provided by Cloudflare.

Save or update the changes.

Verify Nameserver Update: Return to your Cloudflare dashboard and click the "Check Now" or "Recheck Nameservers" button (this might take some time). Once Cloudflare confirms the nameserver change, your site will be on Cloudflare's network.

3. Enabling "Under Attack" Mode:

Log into Cloudflare: If you aren't already, login to your Cloudflare dashboard.

Select Your Site: From the home page, click on your website/domain name.

Access Quick Actions: On the Cloudflare dashboard for your domain, look for the "Quick Actions" section.

Enable "Under Attack" Mode: Click on the "Under Attack Mode" button. This will challenge all visitors to pass a JavaScript test before accessing your site, ensuring that bots and malicious actors are blocked.

Note: Use the "Under Attack" mode judiciously. While it provides an added layer of security during an active attack, it can affect user experience for legitimate visitors. When the attack subsides, consider deactivating this mode.

That's it! By following these steps, you should have successfully registered on Cloudflare, changed your domain's nameservers to utilize Cloudflare's services, and activated the "Under Attack" mode for added security.