Adding a Header or a Footer to all Slides

Https://help.libreoffice.org/Impress/Adding_a_Header_or_a_Footer_to_All_Slides

Every Slide is based on a slide master. The text, pictures, tables, fields or other objects, and the slide master are visible as a background on all Slides that are based in that slide master.

Masters exist for slides, notes, and handouts. To edit a slide master, choose view-master-slide Master. Click The Close master view icon in the Master View toolbar, or choose view-normal, to leave the slide master. To edit a notes master, choose view-master-notes Master. Click The Close master view icon in the Master View toolbar, or choose view-normal, to leave the notes master. To edit a handout master, click the Handout tab above the slide. Click The Normal tab to leave the handout master. adding predefined header or footer objects

Every type of master has some predefined areas to hold the date, footer, and slide numbers.

When you switch to the master view, you can move this areas to any position on the master. You can enter additional text and resize the areas. You can select the contents of the areas and apply text formats. For example, can change the font size or color.

A predefined Header area was available only for notes and handouts. If you are want a header on all slides, you can move the Footer section on the slide master to the top.

Objects that, insert on a slide master are visible on "All slides" are "on" that based master. ChooseView-header and Footer.
For a dialog with two tab pages:SlideandNotes and HandoutsWhere can enter contents to the predefined areas.
By default, theDate and TimeThe checkbox is enabled, but the "format is" set to Fixed and the "Text input box is empty", so no date and "is" visible on the Slides.
By default, theFooterThe checkbox is enabled, but the "text input box is empty", so no footer is visible on the slides.
By default, theSlide NumberThe checkbox is cleared, so no slide numbers are visible. Enter or select the contents that should is visible on all slides. If you are want to change the position and formatting of the Master objects, chooseview-master-slide Master.
You are slide master with areas near the bottom. You can move the areas, and you can select the fields and apply some formatting. can also enter some text here which would be shown next to the fields. Click the date area and move the time and date field. Select the <date/time> field and apply some formatting to change the format for the "date" and "All slides." The same applies to the Footer area and the Slide number area.adding text objects as header or footer objects

Can add a text object anywhere on the slide master. Choose view-master-slide Master. On the Drawing bar, select the Text icon. Drag in the slide master to draw a text object, and then type or paste text. Choose View-normal when you are finished.

You can also add fields, such as the date or page number, to a header or footer by choosing insert-fields.

Can hide the header or footer on the current slide by choosing Format -slide Layout, and clearing the Ob jects on background check box.