http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Installing_Socket_Components

The socket components are not installed by default. To use the socket components, you must install the dclsockets<.bpl> package.

To install the socket components:

1. Select Component > Install Packages.
2. In the Install Packages dialog box, click Add.
3. In the Add Design Package dialog, browse to C:\Program Files (x86)\Embarcadero\Studio\19.0\bin.
4. Select dclsockets250.bpl, and click Open.
5. Click OK to dismiss Install Packages dialog.
6. The socket components (TClientSocket and TServerSocket) are listed in the Internet category of the Toot Palette.

Note: These steps are one-time installation instructions. The socket components should be available for all future projects.