If you want to add a leading zero to data in Excel cells, you need to write the number as a string.
The [Numeric Formatting] logic makes it possible to convert numbers into strings of any format.

• [Numeric formatting]

URL:https://www.hulft.com/help/en-us/DataSpider/dss42sp2/help/en/mapper/document/logic/decimalFormat.html

If you change [Format] to [Specify Format], you can write from an Excel adapter by specifying the type in [String].
For more details on [Format], please refer to following DataSpider Help:

• [Excel]-[Write]-[Properties]

URL:https://www.hulft.com/help/en-us/DataSpider/dss42sp2/help/en/adapter/file/excel_put_data.html

■Supplementary
　As described in the help above, the [Format] of the writing process is available for the [Date] and [Numeric] types.

■Note
　The following is a description of the operation when [Insert] is checked. However, in the current operation of the xlsx format, the data is handled internally in the [standard] type and then written according to the format to which it is written. For this reason, even if you set [String] on the Excel side beforehand, the Excel adapter cannot write the leading "0".
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　　The format used is the insertion position format. Even if you specify [Format and Write] in [Format Setting], it will be invalid.
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　If the above applies, please use the xls format or uncheck [Insert].