In the Sumo Logic Search page, the keyword search term before the first pipe character (|) is case-insensitive. To find case sensitive matches, use the parse regex operator to drop matches that are case-sensitive.
For example, if you wanted to match all lowercase info, you could use this query:
info | parse regex "(?<dummy>info)"
<dummy> is a user added field that is not used for anything other than to enforce that "info" is all lowercase.
To convert a string to all lowercase or all uppercase letters, you can use the toUpperCase and toLowerCase operators.