Button that goes to another page and returns the value passed

Question

Hello, I would like to know how to make a button to get data from another page...type if in page1 I inform the protocol and valid with a captcha and click on send,I would like to know how to send this to get only the protocol I typed in the last page .... example have this page with all protocols I want to pick up only what I typed

This is the code you send after you fill in the protocol and the captcha aew field has the button you send Follow the code see if it’s right.....

public String insert() {
        try {
                if(ca.execute()){

                try {

                 this.getprotocoloString();


                } catch (Exception e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }

                }
        } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
        }
        return protocolo;
}