In Multistore mode, you can add a selection of products to other shops and/or make them active (or not) in other shops too.
Products can be available in various shops, and this sharing action can be done in the MultiStore Sharing Manager in the Properties panel.
Tick/untick 'Present' for the corresponding shops.
In this panel, you can also enable/disable products in each shop by ticking/unticking 'Active'.
You could also use the mass-association icons / on the toolbar after selecting the concerned stores (selected lines).