How to assign the variable data received from server.
The first question is how to ask an intelligent question. Your Arduino is the server. It is sending data.
If you want the client to display the data, and have the data editable on the client, AND have the edited data on the client sent back to the server, that is possible.
But NOT until all of your f***ing tags match. This is STILL crap:
client.println(F("HTTP/1.1 200 OK"));
client.println(F("Content-Type: text/html"));
client.println();
client.println(F("<META HTTP-EQUIV=REFRESH CONTENT=5 URL=>"));
client.println(F("
Web application V1.0
"));
client.print(F("
DATE: = "));
client.print(" <color=blue> latitude: <input type=text name=01 value=");
client.println(latitude);
client.print(" <color=black> Longitude: <input type=text name=01 value=");
client.println(longitude);
client.println("");
client.println("");
client.println("");
The highlighted end tags DO NOT HAVE MATCHING start tags.
makes no sense except on a form, which you do not have.