Right click on an existing procedure and select "generate execute statement", which would then place a script to call the procedure with all parameters stubbed out into your clipboard.
For example, if this procedure existed:
create procedure myschema.sp_test(id out number, name in varchar2, description in varchar2)
as
begin
null;
end;
The generated call might look like:
declare id_out number;
begin
myschema.sp_test(id=>id_out, name=>,description=>);
end;
or even a simpler output of:
myschema.sp_test(id=>, name=>,description=>);