[Excel] (Custom functions) Add LAMBDA support article

Author: alison-mk

docs/excel/custom-functions-lambdas.md

@@ -0,0 +1,17 @@
+---
+title: Use custom functions with LAMBDA functions
+description: Combine custom functions with specific LAMBDA functions.
+ms.date: 12/05/2025
+ms.localizationpriority: medium
+---
+
+# Use custom functions with LAMBDA functions
+
+![The BYCOL LAMBDA function used with a custom function.](../images/excel-custom-functions-lambda-function.png)
+
+[LAMBDA functions](https://support.microsoft.com/office/lambda-function-bd212d27-1cd1-4321-a34a-ccbf254b8b67) are custom, reusable Excel functions that users can create without JavaScript. Custom functions add-ins created with Office JavaScript APIs are compatible with the following LAMBDA functions.
+
+- [BYCOL](https://support.microsoft.com/office/bycol-function-58463999-7de5-49ce-8f38-b7f7a2192bfb)
+- [BYROW](https://support.microsoft.com/office/byrow-function-2e04c677-78c8-4e6b-8c10-a4602f2602bb)
+- [MAKEARRAY](https://support.microsoft.com/office/makearray-function-b80da5ad-b338-4149-a523-5b221da09097)
+- [MAP](https://support.microsoft.com/office/map-function-48006093-f97c-47c1-bfcc-749263bb1f01)

docs/images/excel-custom-functions-lambda-function.png

@@ -700,6 +700,9 @@
     - name: Work with formula value preview
       href: excel/custom-functions-formula-value-preview.md
       displayName: Excel, Custom Functions
+    - name: LAMBDA functions
+      href: excel/custom-functions-lambda.md
+      displayName: Excel, Custom Functions
     - name: Batch custom function remote calls
       href: excel/custom-functions-batching.md
       displayName: Excel, Custom Functions