From the section All posts you can edit or delete existing posts one by one or even bulk delete them.
To edit a post, simply hover over it, and a menu will show up where you can choose to Edit or Quick edit.
If you want to delete a post, simply select the Trash option from that same menu under each post.
To bulk delete posts, check all boxes next to the ones you wish to delete and select the Move to trash option from the drop-down menu.
Keep in mind that WordPress stores the posts you delete in your Trash for 30 days. You can click on the Trash tab if you change your mind at some point in that time frame. From there, you can either Restore or Delete permanently a post.
