discord py edit message
await message.edit(content="newcontent")
#for embed you need to create a new one
await message.edit(embed=newembed)
discord.py send messages
#plain text
await message.channel.send("content")
#with a embed
await message.channel.send("content", embed=embed_name)
#with a file/image
await message.channel.send("content", file="file/image path")