There are two ways to include or insert video files into WordPress posts
Add video from the Web:
Step 1 : Log in to your WordPress.com account and click the Add New link from the Posts menu.
Step 2 : Click the Add Video icon, then click the From URL tab.
Step 3 : Type the URL (Internet address) of the video in the Video URL text box. Video providers, such as YouTube, usually list the direct link for the video file on their sites; you can copy and paste it into the URL text box in the Add Video window.
Step 4 : Click the Insert into Post button. WordPress inserts piece of code called a “short code”. That short code tells WordPress to embed the video within your post so that your readers can play, watch and listen to the video directly on your WordPress blog.
Upload a video file from your own computer and post it to your blog:
Step 1 : Log in to your WordPress.com Dashboard and click the Add New link from the Posts menu. The Add New Post page opens.
Step 2 : Click the Add Video icon.
Step 3 : Click the Select Files to Upload button. An Open dialog box appears.
Step 4 : Select the video file you want to upload and click Open (or double-click the file). The file uploader window in WordPress reappears, showing a progress bar while your video uploads. When the upload is complete, a box containing several options appears.
Step 5 : Type a title for the file in the Title text box, a caption for the file in the Caption text box, and a description of the file in the Description text box.
Step 6 : Click the File URL button.
Step 7 : Click Insert into Post. WordPress inserts a link to the video into your post.