I read my LibreOffice/OpenOffice documents with tablets and smartphones. Is there any software for the ODT -format which allows me to edit such files. I often find things which I should fix and would like to note that to the file.
Currently there is no such software. However, the LibreOffice team is working on an app. A prototype was reviewed e.g. here, if you want to take a look. No release date so far, but it will hopefully hit the market soon -- it is really strongly needed, as there is not a single Office app capable of working with OpenDocument formats (aside from AndrOffice, which is a spreadsheet-only app and obviously discontinued, as it is no longer listed on the playstore).
Until then: There's a Viewer app available at least, OpenOffice Document Reader...
UPDATE: Meanwhile, things have changed, and you have the choice between AndrOpen Office and TextMaker Mobile for read/write access, as well as Coffice and the already mentioned OpenDocument Reader for read-only access.
TextMaker Mobile is the only word processor that lets you open / save
This app is full of features, e.g., including a very good on-the-fly spell checker, footnotes, endnotes, comments, track changes, embedding of any font, access to several file hosting services etc., all TrueType and openType fonts can be embedded, it has a broad range of formatting and layout options, access and so much more.