There are a few WordPress plugins that you can use to display a pop-up text banner for each post. Here are a few of the most popular options:

1. Popup Anything

Popup Anything is a freemium plugin that allows you to create and display pop-ups on your website. To create a pop-up text banner for each post, you can use the following steps:

1. Go to Plugins > Add New and search for “Popup Anything”.
2. Install and activate the plugin.
3. Go to Popup Anything > Add New to create a new pop-up.
4. In the Popup Type dropdown menu, select Text.
5. In the Popup Content field, enter the text that you want to display in the banner.
6. You can also customize the appearance of the banner by changing the colors, fonts, and other options.
7. Once you are happy with the banner, click the Publish button.

To display the banner on each post, you can add the following shortcode to your post template:

[popup-anything id="YOUR_POPUP_ID"]

Replace YOUR_POPUP_ID with the ID of the pop-up that you created in the previous step.

2. Popup Maker

Popup Maker is another premium plugin that allows you to create and display pop-ups on your website. To create a pop-up text banner for each post, you can use the following steps:

1. Go to Plugins > Add New and search for “Popup Maker”.
2. Install and activate the plugin.
3. Go to Popup Maker > Add New to create a new pop-up.
4. In the Popup Type dropdown menu, select Text.
5. In the Popup Content field, enter the text that you want to display in the banner.
6. You can also customize the appearance of the banner by changing the colors, fonts, and other options.
7. Once you are happy with the banner, click the Publish button.

To display the banner on each post, you can add the following shortcode to your post template:

[popup id="YOUR_POPUP_ID"]

Replace YOUR_POPUP_ID with the ID of the pop-up that you created in the previous step.