I would like to add my company Id in the JlinkedApply tag

Sorry for the delay in getting back to this. The easiest (though awkward) way to get your company ID is the following:
* Go to the Apply Button configuration tool
* Type in your company name and select it from the drop down
* Add an email address and title for the 'position' you're creating (this can all be fake)
* Hit the "Get Code" button

In the bottom textbox, you'll see the code for the Apply button. In there will be a line like data-companyid="365848" . That's your company ID.

Sorry it's so confusing. There used to be a way to fetch the ID from your actual company page on LinkedIn, but it seems like they removed that.

Thanks,
Alex