Hello, Jack. They both mean every day and can be used interchangeably. Although of the two sentences, the first sounds the most natural.

They have different meanings. 'On a daily basis' means once a day or each day. It indicates frequency. This is the phrase you need. 'Daily' corresponds to the two-word adverb 'EVERY DAY' : "I study every day" 'Day-to-day' refers to the routine of normal life, often meaning commonplace or 'workaday'. For example, 'day-to-day worries' are worries about being late for work, noisy neighbours and suchlike (as opposed to more important, long-term or wider issues). We also talk about day-to-day chores, day-to-day responsibilities, or the day-to-day running of a business - in all cases, this means ordinary circumstances as opposed to special circumstances. 'Day-to-day' corresponds to the one-word adjective EVERYDAY: "The everyday problems of working people".

Daily basis means doing something every day with certainty. Day to day means that it may be a struggle. For example, " I only have a short time to live. I am taking it day by day."