How do I add python libraries to an AWS lambda function for Alexa?

You may want to look into using frameworks such as zappa which will handle packaging up and deploying the lambda function for you.

You can use that in conjunction with flask-ask to have an easier time making Alexa skills. There's even a video tutorial of this (from the zappa readme) here

The official documentation is pretty good. In a nutshell, you need to create a zip file of a directory containing both the code of your lambda function and all external libraries you use at the top level.

You can simulate that by deactivating your virtualenv, copying all your required libraries into the working directory (which is always in sys.path if you invoke a script on the command line), and checking whether your script still works.

As it is described in the Amazon official documentation link here It is as simple as just creating a zip of all the folder contents after installing the required packages in your folder where you have your python lambda code.

As Vineeth pointed above in his comment, The very first step in moving from an inline code editor to a zip file upload approach is to change your lambda function handler name under configuration settings to include the python script file name that holds the lambda handler.

lambda_handler => {your-python-script-file-name}.lambda_handler.

Other solutions like python-lambda and lambda-uploader help with simplifying the process of uploading and the most importantly LOCAL TESTING. These will save a lot of time in development.