// on top of your script under includes.
new Text:sample; 

//on gamemode init
sample = TextDrawCreate(240.0,580.0,"Soomro");
    

public OnPlayerCommandText(playerid, cmdtext[])
{
    if(!strcmp(cmdtext, "/time", true))
    {
        TextDrawShowForPlayer(playerid, sample); // show the text draw we just created above in the variable sample.
        SetTimerEx("TimeUp", 10000, false, "i", playerid); // Set 10 seconds 10000 ms = 10 sec
        return 1;
    }
    return 0;
}
forward TimeUp(playerid);
public TimeUp(playerid)
{

    TextDrawDestroy(sample); //Destroy the created text draw.
    return 1;
}