i have two different isp (internet connection).i want to collect speeds and get a higher single speed.how can i do that??

You can't.
What you can do is to "load balance" your "connections" over the two ISP.
Look for various tuto's and posts in this forum. Including PCC (per connection classifier).

To have "one" increased speed (like getting higher speed when testing with Ookla)
you would need on the server side as well a unit that combines the "streams" via MPTCP etc.