How to tag the user that send the message discord.py code example

Example 1: discord.py message user

if message.content == "dm":
        await message.channel.send("Dming user")
        dm = await message.author.create_dm()  # Creates a dm channel with the user
        await dm.send("What you want to send")  # Sends the user the message

Example 2: store message sent by user in string discord py

response = client.wait_for_message(author=ctx.message.author, timeout=30) 
myvar = response.content  

Make sure to Define ctx and message if you want it to be controlled by a command