First insert your Text Box, I’m using the Insert > Shapes > Text Box option.
Apply text now or at a later time.
Right click within a text Box and opt to Format Text Box.
In the Preview section, de-select the borders that you do not want to appear.
Give the line a suitable colour and preferred width. OK.

You can also put border sides around an inserted image or pasted photo/picture. My image in the example below, is inside the Text Box and is positioned and resized as required.
Right click the image, Format Picture.

Click the Colours & Lines tab and again de-select what you don’t want as before and change the Line colour and width as required.

You can change a border of an existing box/image by again right clicking, Format, and add a border side by selecting a side (deselect what you don’t want or is already a border side) with colour/width, or remove borders sides by de-selecting as before.

If adding a different colour, the transparency will be changed. Change to suit by using the slider/up/down arrows.
Check print Preview tom see result.
Click the image below to see the above in a short video.