Click the Text tag and type in the text you want in the Caption box. Make sure image captioning is switched on and the button in the top right shows: 
You can use the following characters to include information in the caption:
| +p | file path |
| +f | filename |
| +e | extension |
| +it | File Time (hh:mm) |
| +id | File date (dd-Mmm-yy) |
| +t | time (hh:mm) |
| +d | date (dd-Mmm-yy) |
| +x | EXIF data, see below |
| +a | IPTC data, see below |
| ++ | + |
Click the 
button to set the font style and size. Click the “Fore” button set set the color of the text. If you want a background click the check box and click the “Back” button to select a background color.
Set your required location, opacity and margins.
If you want a drop shadow background click the “DrSha” check box. The 3 boxes below control the size and position of the drop shadow.
Adding an image or visible watermark
Full list of codes available including EXIF and IPTC
| +n | Newline (for multi-line text) |
| +p | File path |
| +f | Filename |
| +e | File extension (eg JPG) |
| +t | Current time (hh:mm) |
| +d | Current date (dd-Mmm-yy) |
| +it | File Time (hh:mm) |
| +id | File date (dd-Mmm-yy) |
| +xt | EXIF Time (hh:mm) |
| +xd | EXIF date (dd-Mmm-yy) |
| +xc | EXIF Comment |
| +xe | EXIF Description |
| ++ | + |
| +a5 | IPTC Object Name |
| +a15 | IPTC Category |
| +a20 | IPTC Supplemental Category |
| +a25 | IPTC Keywords |
| +a40 | IPTC Special Instructions |
| +a55 | IPTC Date Created |
| +a60 | IPTC Time Created |
| +a90 | IPTC City |
| +a92 | IPTC Street |
| +a95 | IPTC State |
| +a100 | IPTC Country Code |
| +a101 | IPTC Country |
| +a105 | IPTC Headline |
| +a110 | IPTC Credit |
| +a115 | IPTC Source |
| +a116 | IPTC Copyright Notice |
| +a118 | IPTC Contact |
| +a120 | IPTC Caption/Abstract |
| +a122 | IPTC Writer/Editor |
Note all the IPTC data is available and can be accessed by using +aNNN where NNN is the code number. Where IPTC data has multiple values these are joined together and separated by a “;”