The Parallel dropdown will appear only when Parallel Computing Toolbox is installed and licensed.
First, run the command ver. The output of ver will show everything that is installed, regardless of whether or not you are licensed for that product. If Parallel Computing Toolbox is not in your ver output, then please refer to the following article:
Why does the "ver" command not list all the products that I have installed?
If Parallel Computing Toolbox is listed in the ver output, but the Parallel dropdown is still missing, then this may be a licensing issue. Run the following command to check the status of your Parallel Computing Toolbox license:
>> license checkout Distrib_Computing_Toolbox
If the answer is anything other then 1, then you will want to make sure your license is up to date and has Parallel Computing Toolbox on it. For an individual license, you can update your license from within MATLAB by going to MATLAB's Help menu > Licensing > Update Current License. Be sure to select the the license that has a valid copy of Parallel Computing Toolbox on it when doing this. If you have multiple licenses and not sure which one to select, please refer to the following article: Which products are included in my license?
If you have a network license and are not sure how to update the license on the network license manager, please either consult with your license administrator or refer to the following article:
How do I update my existing network installation with the new license file I received?
If the issue persists after following these steps, or if you need additional assistance, please contact support using the following link: