When a packet list or packet file is open the edit menu will contain a "Find" option:

Additionally you can hold CTRL + F3 to bring up the Data Search Dialog
The search dialog consists of a search edit box as well as three fields to specify the exact type of search you want to do:

The length field allows you to specify the size of the search you want to do. The options are:
The format field tells the search function what type of comparison should be used:
If you are comparing a Unicode or ASCII string you can also specify case sensitivity. By default searches are not case sensitive.
Not all Formats, Options, and Lengths can be combined together:
| String | BYTE | WORD | DWORD | Case Sensitive | |
| ASCII | Y | N | N | N | Y |
| Unicode | Y | N | N | N | Y |
| Dec | N | Y | Y | Y | N |
| Hex | Y | Y | Y | Y | N |
| Oct | N | Y | Y | Y | N |
| Bin | N | Y | Y | Y | N |
Hex strings are a special case. If you specify the "Hex" format with the "String" length then the input will be converted
to an array of bytes. Hex digits in a hex string should be entered as groups of two characters: each representing one byte. There
should be no spaces between the hex digits. If three characters are entered, the last will be padded with a leading "0":
"3A7F" compares \x3A\x7F.
"3A7" compares \x3A\x07".