> For the complete documentation index, see [llms.txt](https://docs.hex-rays.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hex-rays.com/8.5/user-guide/disassembler/navigation/how-to-enter-an-identifier.md).

# How to Enter an Identifier

An identifier is a name which starts with a letter and contains only letters and digits. The list of allowed characters is specified in config file [IDA.CFG](/8.5/user-guide/configuration/configuration-files.md). All names are case-sensitive.

Maximal length of a name is specified in the configuration file too:

```
        MAX_NAME_LENGTH=120     // Maximal length of new names
```

Default is 120.

Some assemblers have a shorter name length limit, beware!

IDA will warn you if you enter an illegal name.


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