Searching for App Search

Many leading Apps do not have a search function. For example iCloud offers Pages, Numbers, etc, but there is no way to search to find a document within the App. I have over 100 Excel spreadsheets on my iPad and have to scroll through the whole list to fund the one I need. Open source search widgets are widely available. There is no reason not to add a search (Apple has one on the iCloud web site). No Apple for this teacher!